15 states where regular gas costs less than $4 a gallon

A driver pulling up to a gas station reads one number before anything else, and the state beneath the tires goes a long way toward setting it. Filling a tank is a chore people repeat on a schedule, with no chance to haggle over the posted sign. Commuters, delivery workers, and families planning road trips all absorb the difference between a cheap fill-up and a costly one, and that difference lands in the same household budget that covers rent and groceries. A few cents per gallon can seem trivial at a single stop. Across dozens of visits to the pump in a year, those cents pile up into money that could cover something else. Knowing where fuel costs less helps anyone deciding where to refuel before crossing a border, how to route a long trip, or what to set aside for transportation.

California motorists pay an average of $6.0816 for a gallon of regular, $1.8115 above the $4.2701 national average. At that spread, a hypothetical 15-gallon purchase in California runs about $27 more than the same amount at the national rate. Hawaii's regular average reaches $5.6483, and Washington state's hits $5.3421. Readings such as these show how far apart prices across the country can drift, and a single national average hides the distance between the extremes. Someone who lives near a state line, or who crosses several in a week, meets those swings at the register. Motorists hunting for relief at the low end of the scale need a clear picture of where regular gas slips under $4 a gallon and how mid-grade, premium, and diesel behave in those same places.

AAA publishes average fuel costs for all 50 states plus the District of Columbia, with separate columns for regular, mid-grade, premium, and diesel. Its data carry a date of 10/22/26 and run to four decimal places. Fifteen of the 51 entries post a regular-gas average below $4 a gallon, and this list covers every one of them. Maryland, the next entry above the line at $4.0507, falls outside the group, which leaves a clean break between these states and the rest of the table. The items ahead run from the lowest regular price to the highest within the 15, and each one sets the other three grades beside the regular price. The table reports dollar amounts alone and offers no explanation for why any state charges what it does. The comparisons that follow stick to what the table shows.

Illustration: Quartz

North Carolina drivers pay $3.5508 for a gallon of regular, the lowest price in the table and $0.7193 under the national average. Against California, the most expensive state for regular, the distance swells to $2.5308 per gallon. A North Carolina motorist can buy more than 1.7 gallons for what a single gallon fetches in California.

Georgia, the next state up the list, charges $0.1522 more for regular. The jump between those two states exceeds half of the $0.2747 spread separating Georgia from Delaware, the final state under $4. The other 14 states in the group fit inside that band. North Carolina stands apart, with no rival within 15 cents of its price.

Mid-grade runs $4.0244 in North Carolina, the cheapest mid-grade figure among all 51 entries. A driver there who trades up one grade pays less than motorists buying regular in 36 entries, every one above the $4 mark. Trading up adds $0.4736 per gallon.

North Carolina's premium, at $4.4313, undercuts every other premium price in the table. The state's top grade costs less than regular in 14 states, including Pennsylvania at $4.4772, Wyoming at $4.4493, and Montana at $4.4391. Moving from regular to premium adds $0.8805 per gallon, about 1.9 times the mid-grade increment.

Diesel in North Carolina sells for $5.5858, below every other entry and $0.1552 beneath Georgia's. The state's most expensive fuel undercuts regular in California and Hawaii. Hawaii's regular, at $5.6483, exceeds North Carolina diesel by $0.0625, the narrower of the two margins. Inside North Carolina, the gap between diesel and regular reaches $2.0350.

North Carolina posts the bottom figure in all four columns, a sweep no other entry matches. Georgia comes closest in each grade, trailing by $0.1522 on regular, $0.1708 on mid-grade, $0.1552 on diesel, and $0.1972 on premium. Across the three gasoline grades, the cushion widens with each grade a driver climbs. A North Carolina driver who buys premium saves more against Georgia than one who buys regular, by 4.5 cents a gallon.

Illustration: Quartz

Georgia drivers pay $3.7030 for a gallon of regular, $0.5671 under the national figure and $0.1522 above North Carolina. Texas follows at $3.7611, giving Georgia a $0.0581 cushion over the next state on the list. The gap separating Georgia from North Carolina stretches more than twice as wide as the margin protecting it from Texas. On regular, Georgia clusters with the states behind it, and North Carolina stands alone.

Georgia holds the runner-up spot in all four fuel columns among the 51 entries in the table. Mid-grade costs $4.1952, premium $4.6285, and diesel $5.7410, and North Carolina beats each of those prices. The same two states claim the bottom pair of slots in every column. Texas trails Georgia by $0.0824 on mid-grade but by $0.0261 on premium and $0.0246 on diesel. The Texas deficit shrinks by more than two-thirds on the pricier fuels.

Georgia's premium undercuts regular gas in nine states: Alaska, California, Hawaii, Idaho, Illinois, Nevada, Oregon, Utah, and Washington state. A California motorist buying regular pays $1.4531 more per gallon than a Georgia driver choosing premium. Georgia's diesel, the dearest fuel in its table, sells for $0.3406 less than California's regular.

Stepping up from regular to mid-grade adds $0.4922 in Georgia, and premium sits $0.9255 above the base grade. Both increments exceed North Carolina's equivalents of $0.4736 and $0.8805. North Carolina's lead over Georgia widens as a result, from about 15 cents on regular to 17 cents on mid-grade and about 20 cents on premium. Diesel runs $2.0380 above regular in Georgia, three-tenths of a cent more than North Carolina's $2.0350 spread. The diesel difference between the two states, about 16 cents, tracks the regular one.

A Georgia driver who buys premium or diesel pays less than motorists in 49 of the other 50 entries. The state's edge persists at every pump handle, with North Carolina as the lone exception at each grade. No other entry stays within 20 cents of North Carolina on all four fuels.

Illustration: Quartz

Texas drivers fill diesel tanks at $5.7656 a gallon, the third-lowest diesel price among the 51 entries in the state table. North Carolina and Georgia alone undercut it, and every other state, plus the District of Columbia, charges more for the fuel. Georgia's edge over Texas amounts to $0.0246, less than 3 cents a gallon. A diesel buyer crossing between the two states would struggle to spot the difference at the pump.

California sets the diesel ceiling at $8.4854, and Texas comes in $2.7198 below it. Washington state asks $7.3098, leaving Texas ahead by $1.5442. Filling a 20-gallon diesel tank in Texas costs about $54 less than the same purchase in California and about $31 less than in Washington state. Gaps that wide turn the choice of where to refuel into real money for anyone who runs a diesel engine on long routes.

Texas keeps the same two rivals ahead of it on every grade. Regular costs $3.7611, mid-grade $4.2776, and premium $4.6546, and in each column North Carolina and Georgia post the sole lower figures. The three states hold the cheapest three spots for all four fuels, and no fourth state slips past Texas on any of them. A Texas driver buying premium pays $1.4270 less than a California driver buying regular.

Texas regular undercuts the national average by $0.5090 a gallon, a savings of $5.09 on a 10-gallon fill-up. Each step from regular to another fuel adds to the bill. Mid-grade runs $0.5165 above regular, premium $0.8935 above it, and diesel $2.0045 above it. Diesel buyers absorb the steepest climb, a markup more than twice the size of the jump to premium.

Texas regular sits inside a tight cluster near the front of the list. Georgia sells regular for $0.0581 less per gallon, and Tennessee asks $0.0628 more. Neither gap reaches 7 cents. Georgia, Texas, Tennessee, and Louisiana fit within a 12.9-cent spread on regular. A Texas vehicle owner pays less than drivers in 48 of the other 50 entries in the table, whatever fuel the tank takes.

Illustration: Quartz

Tennessee posts a $3.8239 regular-gas average, yet its diesel costs $5.9725 a gallon, the highest diesel price among the first eight states on this list. The two fuels sit $2.1486 apart at Tennessee pumps. Among the 15 states here, Indiana and Delaware alone show a wider split between regular and diesel, and both charge more for regular than Tennessee does.

Texas sells regular for $0.0628 less than Tennessee, but its $5.7656 diesel undercuts Tennessee's by $0.2069. The diesel difference between the two states runs more than three times the size of the regular-gas gap. Georgia stretches the contrast. Its regular costs $0.1209 less than Tennessee's, and its $5.7410 diesel leaves Tennessee $0.2315 higher. A Tennessee driver who switches from regular to diesel faces a steeper climb than a Texas or Georgia driver making the same move. North Carolina's $5.5858 diesel falls $0.3867 below the Tennessee figure.

Six states with costlier regular gas than Tennessee sell cheaper diesel. Louisiana, South Carolina, Mississippi, Arkansas, Alabama, and Oklahoma each charge between $0.0081 and $0.1273 more for a gallon of regular, yet each posts a diesel average below Tennessee's. Oklahoma's regular runs $0.1273 above Tennessee's, the largest margin of the six, yet its $5.9259 diesel comes in $0.0466 cheaper. Tennessee lands 10th of the 15 on diesel, and Missouri, Kansas, Kentucky, Indiana, and Delaware are the five states that cost more.

Mid-grade and premium gasoline keep Tennessee competitive. Mid-grade averages $4.2975, the fourth-lowest price for that grade in the group and $0.0024 below Missouri's, the next one up. Stepping up from regular to mid-grade adds $0.4736 a gallon at Tennessee stations. Premium reaches $4.7028, seventh among the 15 and $0.8789 above regular. Across all three gasoline grades, Tennessee stays within the cheaper half of the list.

Diesel is the one fuel that pushes Tennessee into the pricier half. A Tennessee motorist with a gasoline car keeps most of the state's pump advantage, while a diesel buyer surrenders much of it. The state's low regular price describes what gasoline buyers find and says little about anyone filling a diesel tank.

Illustration: Quartz

Louisiana's regular gasoline averages $3.8320 a gallon, a fraction of a cent above Tennessee's, yet its diesel sells for $5.8082 and beats Tennessee's $5.9725 by 16 cents. The two states sit side by side at the regular pump and split apart once a driver reaches for the diesel nozzle. Louisiana charges $0.0081 more per gallon of regular, a margin too thin to change anyone's route. Twenty gallons of regular cost a Louisiana driver about 16 cents more than the same fill in Tennessee. Twenty gallons of diesel reverse the math and leave about $3.29 in the Louisiana buyer's pocket. A single gallon of Louisiana diesel saves about what a full 20-gallon tank of regular costs extra.

Louisiana's diesel price is the fourth lowest among the 50 states and the District of Columbia, with North Carolina, Georgia, and Texas the lone cheaper entries. South Carolina comes closest among the remaining under-$4 states at $5.8344, and Mississippi trails at $5.8770. No entry outside the group undercuts Louisiana either. Florida's $5.9900 is the cheapest diesel among the other 36. Diesel gives Louisiana its best placement on any grade in the table, a notch above its fifth-place showing on regular.

Tennessee keeps a slim lead on both higher-octane grades. Louisiana's mid-grade runs $4.3093 against Tennessee's $4.2975, and its premium costs $4.7044 against $4.7028. On premium the difference between the two states shrinks to $0.0016, a sum no buyer would detect at the register. Tennessee's gasoline advantage stays at 1.18 cents a gallon or less on every grade, while diesel tilts toward Louisiana by a far wider spread.

Louisiana belongs to a five-state cluster whose regular averages span $0.0433, from Tennessee's $3.8239 to Mississippi's $3.8672. South Carolina and Alabama fill the middle of that band. Diesel stretches the same five about four times as wide, and Tennessee and Louisiana anchor the two ends. Alabama, at $5.9184, joins Tennessee as the lone members of the cluster above $5.90. Among five states separated by less than a nickel on regular, diesel becomes the clearest point of difference, and Louisiana beats the other four on it.

Illustration: Quartz

South Carolina drivers who buy diesel pay $5.8344 a gallon, $1.9879 more than the state's $3.8465 regular average. Oklahoma, at $1.9747, and Louisiana, at $1.9762, are the sole states among the 15 under $4 with a narrower gap between the two fuels.

Every other state on the list charges diesel customers at least $2 more than regular. Texas comes closest at $2.0045, while Indiana stretches the spread to $2.6982, about 71 cents wider than South Carolina's. South Carolina's diesel price lands fifth-lowest of the 15, behind North Carolina, Georgia, Texas, and Louisiana. Five states in the selection, including Indiana and Delaware, charge more than $6 for the fuel.

South Carolina's regular price sits near the center of a 4.33-cent band that five states on this list share, from Tennessee at $3.8239 to Mississippi at $3.8672. Louisiana, at $3.8320, and Alabama, at $3.8626, fill out the group. South Carolina lands 2.26 cents above Tennessee and 2.07 cents below Mississippi. A motorist choosing among those five would save less than a nickel per gallon on regular.

North Carolina, the other Carolina on the list, undercuts South Carolina's regular price by 29.57 cents. The gap stretches more than six times the width of the Tennessee-to-Mississippi band, a sign of how far North Carolina pulls away from the states that follow it.

South Carolina charges 46.62 cents more for mid-grade than for regular, putting that grade at $4.3127, and premium adds another 40.57 cents to reach $4.7184. The full regular-to-premium distance totals 87.19 cents, close to Louisiana's 87.24 cents and Alabama's 87.05 cents. Premium buyers in those three states face markups that differ by less than a fifth of a cent. Mississippi, at 85.26 cents, posts a smaller distance than any of them.

Diesel buyers fare better in South Carolina than the regular figure would suggest. The state's regular average comes in sixth-cheapest among the 15, while its diesel price comes in fifth. A driver weighing a diesel vehicle against a gasoline one pays a smaller per-gallon penalty for diesel here than in 12 of the other 14 states on this list.

Illustration: Quartz

Alabama drivers pay $3.8626 for a gallon of regular, a figure that undercuts the national average by $0.4075. Six states on this list sell regular for less, and eight charge more. The state's regular price clears the $4 cutoff that defines this list by 13.74 cents.

Alabama belongs to a tight cluster of five states whose regular averages fall between $3.8239 and $3.8672. Tennessee, Louisiana, South Carolina, and Mississippi fill out the cluster, and the distance from its cheapest member to its priciest comes to 4.33 cents. Alabama costs 1.61 cents more than South Carolina and 0.46 cent less than Mississippi. A driver moving among these five states would see per-gallon prices differ by less than a nickel.

Mid-grade erodes Alabama's position, with a $4.3407 average that runs $0.4781 above the state's regular gas, the widest step between those two grades among the five clustered states. The other four add between 46.62 and 47.73 cents. Nine of the remaining 14 states sell mid-grade for less than Alabama does, compared with six that undercut its regular.

Alabama's premium costs $4.7331 a gallon, $0.8705 above its regular price and higher than any other state in the five-member cluster. Indiana, Kentucky, Delaware, and Arkansas alone charge more for premium among the 15, which makes Alabama's top grade the fifth most expensive in the group. Tennessee posts the cluster's cheapest premium at $4.7028, about 3 cents below Alabama.

Diesel costs $5.9184 in Alabama, $2.0558 more than a gallon of regular. Seven states on the list sell diesel for less and seven charge more, which leaves Alabama at the exact middle of the group. Arkansas sits $0.0011 below Alabama, and Oklahoma charges 0.75 cent more. Diesel buyers in Alabama find neither a bargain nor a penalty compared with the rest of this list.

Alabama's standing within the group slides from seventh-cheapest on regular to 10th on mid-grade and 11th on premium, which confines the state's discount to buyers of its least expensive grade.

Illustration: Quartz

Mississippi motorists pay $3.8672 for a gallon of regular, less than half a cent above Alabama's average. Regular is the only grade where Alabama holds the cheaper price, and across a 15-gallon fill-up its advantage amounts to under 7 cents. Climb past regular and the order flips. Mississippi's mid-grade averages $4.3397, a tenth of a cent below the Alabama figure. Premium costs $4.7198 in Mississippi against $4.7331 in Alabama, a difference of 1.33 cents. Every Mississippi shopper who buys a grade above regular pays less than a counterpart in Alabama.

Diesel stretches Mississippi's lead to its widest margin. The fuel sells for $5.8770 in Mississippi and $5.9184 in Alabama, a 4.14-cent gap. A driver filling a 20-gallon diesel tank would keep 83 cents by buying in Mississippi. Among the 15 states with regular below $4, five post lower diesel averages than Mississippi: North Carolina, Georgia, Texas, Louisiana, and South Carolina. Two states with cheaper regular, Tennessee and Alabama, charge more for diesel, and Tennessee's price runs 9.55 cents above Mississippi's.

Mississippi's markups between grades run thinner than Alabama's at every step. Trading up from regular to mid-grade adds 47.25 cents in Mississippi and 47.81 cents in Alabama. The jump to premium costs 85.26 cents in Mississippi, compared with 87.05 cents in Alabama. Diesel lands $2.0098 above regular in Mississippi and $2.0558 above it in Alabama. The spread between the two states' markups grows as the fuel climbs in cost, from about half a cent on mid-grade to 4.6 cents on diesel.

Mississippi's regular price sits inside a tight pack of seven states that extends from Tennessee to Arkansas and includes Louisiana, South Carolina, Alabama, and Indiana. All seven fall within 5.8 cents of one another on regular. Mississippi trails Louisiana by 3.52 cents and beats Arkansas by 1.47 cents. Arkansas also charges 4.03 cents more than Mississippi for diesel. Inside a cluster this compact, the regular price by itself tells drivers little, and the other three fuels decide where a fill-up costs less.

Illustration: Quartz

Diesel costs $6.5775 a gallon in Indiana, the steepest price for that fuel among the 15 states where regular sells for under $4. Delaware follows at $6.3295, close to 25 cents lower. North Carolina charges $5.5858, a full 99 cents below Indiana. Indiana's regular gas, by contrast, sits in the middle of the pack. At $3.8793 a gallon, it comes in ninth of the 15 and costs about 1 cent more than Mississippi's.

Indiana's diesel markup over regular reaches $2.6982 a gallon, the widest spread among all 51 entries in the state table. California, home to the costliest regular gas in the country, posts the second-widest at $2.4038. Delaware comes next at $2.3518, and Nevada carries the narrowest at $1.5218. Indiana outruns California's markup by about 29 cents, a wider margin than the 5 cents separating California from Delaware.

Six entries charge more for diesel than Indiana: California, Washington state, Hawaii, Nevada, Oregon, and Pennsylvania. Indiana undercuts the other 44. Each of the six sells regular gas for more than $4.47. Pennsylvania, the cheapest of them on regular, charges about 60 cents more than Indiana for that grade. Its diesel, at $6.6148, costs about 4 cents more than Indiana's. Diesel buyers in Indiana face prices closer to the country's priciest fuel markets than to the rest of this list.

Indiana's premium gas costs $4.9965 a gallon, the highest premium price in the group and 1.43 cents above Kentucky's $4.9822. Moving up from regular to premium costs Indiana drivers $1.1172, the largest jump among the 15. Florida, where regular averages $4.0570, sells premium for $4.8748. A Florida driver pays about 18 cents more than an Indiana driver for regular and about 12 cents less for premium.

Indiana's mid-grade price of $4.4660 sits 59 cents above regular, the third-biggest step in the group behind Delaware and Kentucky. Across the other three grades, Indiana's sub-$4 regular average reveals little about what its buyers spend. A driver filling a diesel tank in Indiana pays more than diesel buyers in 30 of the 36 entries where regular costs $4 or more.

Illustration: Quartz

Arkansas charges $3.8819 for a gallon of regular, about a quarter of a cent above Indiana's $3.8793, yet its diesel costs $5.9173, or $0.6602 below the Indiana figure. Shoppers comparing the two states at the regular pump would struggle to tell them apart. Diesel buyers would see a difference wide enough to notice on a single receipt.

Sixty-six cents a gallon swells into serious money at the diesel nozzle. Filling a 20-gallon tank in Arkansas would cost about $13.20 less than the same fill-up in Indiana. Anyone who buys diesel in volume sees that discount repeat with every trip to the station. Ten fill-ups of that size would leave about $132 more in an Arkansas driver's pocket. The two states sit side by side on the regular-gas list, yet diesel drivers face two distinct bills.

Arkansas keeps diesel $2.0354 above its own regular price, a narrower spread than Indiana's. Within this group of 15, six states post cheaper diesel than Arkansas: North Carolina, Georgia, Texas, Louisiana, South Carolina, and Mississippi. Eight ask more. Alabama lands closest, at $5.9184, about a tenth of a cent above the Arkansas mark. Oklahoma follows at $5.9259, less than a cent higher. Arkansas diesel buyers sit near the middle of the 15, a far more comfortable seat than the one Indiana diesel buyers occupy.

Premium buyers in Arkansas pay $4.7715 a gallon, more than buyers in all but three of the 15 states: Indiana, Kentucky, and Delaware. Mid-grade in Arkansas runs $4.3752, and Oklahoma joins that trio as the fourth state with a pricier mid-grade. Each step up the grade ladder widens the distance from regular, to $0.4933 at mid-grade and $0.8896 at premium. Indiana outprices Arkansas on both upper grades, by $0.0908 on mid-grade and $0.2250 on premium.

Arkansas shows how little a regular average reveals about the full menu of grades. A state can come within a fraction of a cent of another on regular, then diverge from it by more than 22 cents on premium and by far more on diesel. A low sticker on regular gives diesel and premium drivers a weak guide to what they will spend in Arkansas or anywhere else on this list.

Illustration: Quartz

Missouri drivers pay 34.88 cents a gallon to trade up from regular to mid-grade, the smallest step of any state on this list. Regular averages $3.9511 in Missouri, and mid-grade costs $4.2999. The upgrade adds about 8.8% to the base price. The next-narrowest jump among the other 14 states costs 1.66 cents more, and nine of those states charge between 46 and 52 cents for the same move. Against those nine, a Missouri motorist pays about 12 to 17 cents less per gallon for the switch.

Missouri's thin markup lifts a middling regular price into a stronger mid-grade showing, the fifth-cheapest among the 15. North Carolina, Georgia, Texas, and Tennessee are the four states that sell mid-grade for less. Tennessee beats Missouri by 12.72 cents on regular but by 0.24 cents on mid-grade. Louisiana, South Carolina, Alabama, Mississippi, Indiana, and Arkansas all post cheaper regular averages than Missouri, yet each charges more for mid-grade. The reversal stretches from 0.94 cents in Louisiana to 16.61 cents in Indiana, where mid-grade costs $4.4660.

Missouri's premium average of $4.6807 sits 72.96 cents above regular, and Kansas alone posts a narrower premium gap in the group, at 72.30 cents. North Carolina, Georgia, and Texas are the three states with cheaper premium, which leaves Missouri fourth on that grade. Seven of the 10 states with lower regular prices charge more than Missouri for premium, among them Tennessee, Louisiana, and Arkansas.

Missouri's diesel price of $6.0285 runs $2.0774 above its regular average and breaks from the tight spreads the state shows on gasoline. Ten states in the group sell diesel for less, including Oklahoma at $5.9259 and North Carolina at $5.5858. Indiana, Delaware, Kentucky, and Kansas charge more, with Kansas the closest at 3.32 cents above Missouri.

Missouri's figures expose a blind spot in any list sorted by regular gas alone. The state sits 11th on regular but fifth on mid-grade and fourth on premium, then drops back to 11th on diesel. Drivers who fill up beyond regular gasoline get more value in Missouri than its regular average suggests, while diesel owners find it in the back third of the group.

Illustration: Quartz

Oklahoma drivers pay $3.9512 for a gallon of regular, one hundredth of a cent above the $3.9511 average in Missouri. No shopper could detect a difference so small at the pump. A motorist who bought 100 gallons in each state would spend a single extra penny in Oklahoma. The state holds $0.0488 of room beneath the $4 line, a cushion thinner than a nickel.

Oklahoma's diesel costs $5.9259 a gallon, $1.9747 more than its regular gas and the narrowest gulf between those two fuels among the 15 states on this list. Louisiana comes closest, with a $1.9762 spread. Diesel carries the highest price and regular the lowest in every one of the 15 states, so the diesel margin measures how far each state's full fuel menu stretches. A driver scanning the four prices on an Oklahoma sign sees less distance between the cheapest and costliest choice than in any other state in the group.

Oklahoma's diesel undercuts Missouri's $6.0285 by $0.1026, turning a dead heat on regular into a clear win at the diesel nozzle. Five states on this list charge more than $6 for diesel: Indiana, Missouri, Kansas, Kentucky, and Delaware. Oklahoma stays below that mark, and Delaware's $6.3295 exceeds the Oklahoma price by $0.4036. Eight states in the group sell diesel for less, which leaves Oklahoma's diesel price in the middle of the pack. Oklahoma's narrow fuel spread reflects a regular price that sits high within the group alongside an unremarkable diesel price.

Missouri reclaims the edge on mid-grade, which costs $4.2999 there against $4.3936 in Oklahoma, a $0.0937 difference. Oklahoma charges $0.4424 more for mid-grade than for regular, a smaller step than every state in the group except Missouri and Kansas. Premium averages $4.7006 in Oklahoma, $0.3070 above mid-grade, and Delaware posts the only smaller jump between those two grades among the 15. Kansas and Missouri record the only smaller climbs from regular to premium than Oklahoma's $0.7494.

Oklahoma's price structure rewards households that buy more than one fuel. A family running a gasoline car and a diesel truck pays a smaller markup for the second tank in Oklahoma than in any other state on this list, a benefit that outweighs the hundredth of a cent the state cedes to Missouri on regular.

Illustration: Quartz

Kansas motorists pay $3.9640 for a gallon of regular and $4.3294 for mid-grade, a 36.54-cent gap that Missouri alone beats among the 15 states below $4. Across the remaining 13, moving up to mid-grade costs anywhere from 44.24 cents in Oklahoma to 61.50 cents in Delaware. A Kansas driver who chooses the middle grade gives back less of the cheap-regular advantage than drivers in 13 of the other 14 states on this list.

Premium sells for $4.6870 in Kansas, 72.30 cents above regular and the narrowest premium-to-regular spread in the group. Missouri comes next at 72.96 cents, with Oklahoma close behind at 74.94 cents. Ten other states add between 85 and 93 cents for the top grade, and Kentucky and Indiana each push the surcharge past $1. Kansas premium buyers pay an upcharge at least 12 cents smaller than shoppers in any of those 12 states.

Kansas premium costs less than premium in each of the 36 entries where regular tops $4. Florida posts the cheapest premium outside the 15 at $4.8748, 18.78 cents above the Kansas price. North Carolina, Georgia, Texas, and Missouri are the four entries out of 51 that sell the top grade for less.

Kansas spaces its three gasoline grades in two near-equal intervals. The second interval, from mid-grade to premium, adds 35.76 cents, 0.78 cent short of the first. The balance shows tight pricing running through the entire gasoline lineup, with neither upper grade carrying the discount by itself.

Diesel breaks the pattern at $6.0617 a gallon, $2.0977 above regular. Three states in the group charge more for diesel — Kentucky, Delaware, and Indiana — which leaves Kansas fourth-costliest. The lowest diesel prices on the list, in North Carolina, Georgia, and Texas, all sit at least 29 cents below the Kansas figure.

Kansas regular slips under $4 by 3.6 cents, landing 1.28 cents above Oklahoma and 0.17 cent below Kentucky. Its upper grades make the stronger case. The figures point to a state that rewards drivers who reach for mid-grade or premium while offering diesel buyers little of the same relief.

Illustration: Quartz

Kentucky charges $4.9822 a gallon for premium, the second-highest price for that grade among the 15 states where regular sells for less than $4. Indiana alone asks more for top-tier fuel inside the group. Kentucky's figure stops 1.78 cents short of $5. Its regular average, by contrast, lands at $3.9657 and clears the $4 mark by 3.43 cents.

A Kentucky motorist who trades up from regular to premium adds $1.0165 to every gallon, a markup no state on this list beats except Indiana. Every other state here keeps the jump below 93 cents, and Missouri, Oklahoma, and Kansas each hold it under 75 cents. Filling a 15-gallon tank with premium in Kentucky raises the bill by $15.25 compared with regular.

Kentucky's mid-grade average of $4.5560 sits 59.03 cents above its regular price, the second-widest spread of its kind in the group after Delaware. Indiana trails Kentucky on this measure by 0.36 cent. Across both upper tiers, Kentucky asks drivers for a larger step up than nearly every other state on the list.

Kansas sells regular for $3.9640, 0.17 cent below Kentucky, yet the two states part ways on every higher grade. Kentucky's premium costs 29.52 cents more than the $4.6870 Kansas charges, and its mid-grade runs 22.66 cents above the Kansas level. Even diesel comes in 2.70 cents higher in Kentucky. Two states with near-identical regular prices diverge once a driver moves up the pump.

Kentucky's upper grades also outprice those in Florida, a state that misses the $4 cutoff with regular at $4.0570. Florida lists mid-grade at $4.5398 and premium at $4.8748, and Kentucky exceeds both, by 1.62 cents and 10.74 cents. Maryland, the closest state above the line on regular, prices premium at $4.9797, 0.25 cent below Kentucky.

Diesel in Kentucky averages $6.0887, the third-highest figure in the group behind Indiana and Delaware. The fuel runs $2.1230 more per gallon than regular in the state and 9.87 cents more than diesel in Florida. Every grade except regular costs more in Kentucky than in Florida. Kentucky's spot below $4 pays off for regular-grade buyers and few others.

Illustration: Quartz

Delaware drivers pay $3.9777 for a gallon of regular, about two cents below the $4 threshold and the thinnest cushion of any state on this list. A 7.3-cent margin separates Delaware from Maryland, the first state on the far side of the line. Delaware's regular price comes in 29.2 cents under the national average, less than half the discount North Carolina drivers enjoy at the opposite end of the group.

Delaware undercuts Maryland at all four grades. Mid-grade costs 6.9 cents less than in Maryland, premium 8.2 cents less, and diesel 2.9 cents less. The edge narrows on diesel and widens on premium, yet it survives at every nozzle. Delaware's slim lead on regular belongs to a consistent pattern across the pump.

Delaware's mid-grade, at $4.5927, costs more than in any other state on the list and sits 61.5 cents above regular, the steepest such markup in the group. North Carolina drivers spend 47.4 cents for the same upgrade. Florida, which misses the cutoff with regular at $4.0570, sells mid-grade for $4.5398, about 5.3 cents under Delaware. A Delaware driver who skips regular surrenders much of the state's advantage with the first upgrade.

Delaware's premium, at $4.8977, costs 30.5 cents more than its mid-grade, the smallest gap between those two grades among the 15 states. Oklahoma comes closest at 30.7 cents, and Indiana's spread stretches to 53.1 cents. Kentucky, the entry before Delaware on this list, posts a 42.6-cent step. Of the 92 cents separating Delaware's regular and premium prices, about two-thirds arrives in the move to mid-grade. Delaware drivers willing to buy mid-grade face a modest climb to the top grade.

Delaware's diesel, at $6.3295, runs $2.3518 above its regular price. Indiana alone charges more for that fuel among the 15 states. Florida sells diesel for $5.9900 and Ohio for $6.1692, both below Delaware, though regular costs more than $4 in each of those states. Delaware earns its spot through regular gas, and a diesel buyer there hands over more than drivers in two states excluded from the list.