How do I calculate the fuel cost for a trip?

Divide the distance by your fuel efficiency to get gallons, then multiply by the price per gallon: 240 mi ÷ 28 mpg = 8.57 gal, and 8.57 × $3.40 = $29.14. The per-mile row lets you scale the same trip math to any distance.

What is a good fuel efficiency?

For modern US gasoline cars, a combined 25–30 mpg is typical, and anything over 35 is genuinely frugal. Hybrids run 45–60, while large trucks and SUVs sit in the teens to low twenties.

Does this work with kilometers and liters?

The arithmetic is US units — miles, gallons, mpg. For metric, multiply your L/100km rating by kilometers ÷ 100 to get liters, then multiply by the price per liter. The metric row converts your mpg to L/100km for reference.

How can I cut my cost per mile?

Hold near the speed limit because aerodynamic drag rises with the square of speed, remove roof racks and trunk weight, keep tires at placard pressure, and batch errands to avoid cold starts. Moving from 22 to 25 mpg cuts cost per mile by about 12%.

Why is city driving more expensive?

Braking throws away energy and idling burns it for nothing, so city mpg typically runs 20–30% under highway. Your personal city/highway mix is what the combined number is trying to estimate.

Fuel Cost Calculator | Online Calculators Free

The fuel cost formula

Two steps: gallons = distance ÷ mpg, then cost = gallons × price per gallon. The whole trip reduces to one more useful number — cost per mile = price ÷ mpg — which lets you scale to any distance: $3.50 at 30 mpg is about 11.7 cents a mile, so 1,000 miles is $116.67 before you even enter the distance.

Reading your MPG honestly

The EPA combined figure blends 55% city and 45% highway driving, and real-world drivers typically land a few percent worse — cold starts, short trips, and 75-mph interstate all take their cut. The most accurate input is your own: fill the tank, note the miles since the last fill, divide. Three tankfuls averaged will beat any sticker.

Why city driving costs more

Stop-and-go traffic burns fuel braking and idling, so city ratings typically run 20–30% below highway. Drag rises with the square of speed, which is why the fast lane is the expensive lane, and why a roof box you forgot about shows up at the pump.

Worked example

Weekend trip: 240 miles, the car averages 28 mpg, gas is $3.40/gal.
Gallons: 240 ÷ 28 = 8.57 gal.
Cost: 8.57 × $3.40 = $29.14 one way.
Per mile: 3.40 ÷ 28 = $0.121 — the 480-mile round trip is $58.29.

How to use it

Enter the trip distance in miles — one way or round trip, just be consistent.
Enter your real average mpg (not the sticker’s optimism).
Enter today’s price per gallon.
Read the trip cost, gallons, and the per-mile rate for scaling other trips.