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Fuel Cost Calculator

Calculate the fuel cost of any trip from distance, MPG, and gas price. See total cost, gallons needed, and cost per mile.

Trip details

Trip cost

$37.50

10.71 gallons needed at $0.1250 per mile

Gallons needed

10.71

Cost per mile

$0.1250

Cost per 100 mi

$12.50

Frequently Asked Questions about the Fuel Cost Calculator

How is the fuel cost for a trip calculated?
The calculator divides your trip miles by your MPG to get gallons needed, then multiplies by the price per gallon for total cost. It also shows cost per mile and cost per 100 miles, both derived from that same total, so all four outputs stay consistent.
What MPG should I use for my car?
Use your real-world average if you track fill-ups. Otherwise the EPA combined rating for your make, model, and year is a reasonable starting point, but expect actual mileage to run 10-25% lower, especially in city traffic or with a heavy load.
How do I convert between MPG and L/100km?
Divide 235.21 by your MPG to get L/100km. A car rated 30 MPG works out to about 7.84 L/100km. The scales move in opposite directions, so higher MPG means lower L/100km.
How can I lower the fuel cost of a long trip?
Keep tires at the correct pressure, hold a steady speed at or below 65 MPH, remove roof racks or cargo carriers when not in use, and fill up at stations along your route rather than near tourist stops where prices run higher. Each of these nudges your effective MPG up and your per-mile cost down.
Should I include tolls or just fuel in trip planning?
This calculator covers fuel only. For a complete picture, add tolls, parking fees, and a wear-and-tear allowance. The IRS standard business mileage rate, 70 cents per mile in 2025 and 72.5 cents in 2026, is a useful all-in benchmark for comparison.