Almost nobody pulls in on a dry tank. The needle is at a quarter, or a half, and the question is what this particular stop is going to cost — not what a full tank costs from empty. Pick your vehicle class for the tank size, tell it where the needle is, and choose the grade you actually put in.
The average American fill-up is often quoted at somewhere around $60, and that number is close to useless for any individual driver. Three things move it, and they multiply rather than add.
Tank size varies by a factor of three. A Nissan Versa holds about 10.8 gallons. A Chevrolet Suburban holds about 28. A Silverado 3500HD holds about 36. At $4.48 a gallon that is a $48 stop against a $161 stop, in the same country on the same day.
Grade changes the price by about a fifth. In the week of September 21, 2026 the national averages ran $4.48 regular, $5.06 midgrade, $5.46 premium and $6.53 diesel. Premium is roughly 98 cents a gallon above regular, so on a 19-gallon SUV tank that is about $19 extra per stop.
State prices vary by more than 60%. $3.90 in Indiana against $6.35 in California at the same moment. Same car, same tank, a $34 difference on a 14-gallon fill.
Which is why the calculator asks for your tank, your grade and your price rather than handing you an average.
| Class | Typical tank | Full tank at $4.48 | Range at typical MPG |
|---|---|---|---|
| Subcompact car | ~11 gal | $49 | ~360 mi @ 33 mpg |
| Compact car | ~12.4 gal | $56 | ~440 mi @ 35 mpg |
| Midsize sedan | ~14.5 gal | $65 | ~450 mi @ 31 mpg |
| Full-size sedan | ~18 gal | $81 | ~470 mi @ 26 mpg |
| Hybrid car / crossover | ~11.5 gal | $52 | ~550 mi @ 48 mpg |
| Compact SUV / crossover | ~14.5 gal | $65 | ~420 mi @ 29 mpg |
| Midsize / 3-row SUV | ~19 gal | $85 | ~475 mi @ 25 mpg |
| Full-size SUV | ~24 gal | $108 | ~430 mi @ 18 mpg |
| Minivan | ~19.5 gal | $87 | ~450 mi @ 23 mpg |
| Half-ton pickup | ~23 gal | $103 | ~460 mi @ 20 mpg |
| Heavy-duty pickup | ~34 gal | $152 | ~510 mi @ 15 mpg |
These are class midpoints, not specifications. Within a single nameplate the tank can change with drivetrain and trim — all-wheel-drive versions frequently carry a slightly smaller tank than front-wheel-drive ones, and hybrids give up tank volume to the battery pack while still going further on a fill. Use the table to sanity-check, then put your real number in the box.
This is the part most fill-up calculators skip. If your tank is 14.5 gallons and the needle sits at a quarter, you are buying about 10.9 gallons, not 14.5 — roughly $49 rather than $65. Getting that wrong by a quarter tank is a 25% error on the number you actually care about.
There is a second wrinkle. A quarter on the gauge is not a quarter of the fuel. Gauges are tuned to read conservatively as they approach empty, and the low-fuel light typically comes on with 2 to 3 gallons left — about 10% to 15% of capacity — not at zero. So a fill from "light on" is usually a gallon or two smaller than a fill from a genuinely empty tank, which is why the pump total comes in under the rated capacity almost every time.
Cost per stop is the number you see, but cost per mile is the number that decides your budget. Divide the pump price by your real MPG: $4.48 at 28 mpg is 16.0 cents a mile; the same gas at 18 mpg is 24.9 cents. Over 12,000 miles a year that is $1,920 against $2,988 — a $1,068 difference driven entirely by the vehicle, not by where you fill up or how you drive.
This is also why filling more often does not cost more. Your monthly fuel bill is set by miles driven, MPG and price per gallon. Topping off at a half tank instead of running to a quarter doubles your number of stops and halves the size of each one, and the monthly total does not move. The calculator shows both so you can see they are unrelated — if you want to change the annual figure, the levers are the car, the mileage and the grade.
At about 98 cents a gallon over regular, premium adds roughly 21% to every gallon. On a driver covering 12,000 miles a year at 28 mpg, that is about 429 gallons, so premium costs around $420 a year more than regular.
Whether that money is wasted depends on one word in your owner's manual. If premium is required, the engine's knock control will pull timing on lower octane, and you lose power and some efficiency — the saving is partly illusory, and long-term you are working against the engine's design. If premium is merely recommended, the car is designed to run safely on regular with a small reduction in output, and for ordinary driving the $420 buys you very little. If the manual says regular, premium does nothing at all; octane is a resistance-to-knock rating, not a quality or cleaning rating.
The grade card above prices out all three so you can see the annual figure rather than the 98 cents.