How can I split fuel costs for a road trip?

Divide the total fuel cost by the number of people sharing the ride. Enter the number of passengers and the calculator shows the cost per person.

Fuel Cost Calculator

Q: How do I calculate the fuel cost of a trip?

Divide the trip distance by your vehicle's MPG to get gallons used, then multiply by the price per gallon. A 300-mile trip in a 30 MPG car at $3.50/gallon uses 10 gallons and costs $35.

Q: Does this work for a round trip?

Enter the total distance you'll drive. For a round trip, double the one-way distance before entering it, or enter the round-trip figure directly.

Find the fuel cost of any trip from the distance, your vehicle's fuel economy, and the price of gas — and split it across passengers.

Total fuel cost

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Fuel used

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Cost per person

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Cost per mile

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The fuel cost formula

Gallons = Distance ÷ MPG
Cost = Gallons × Price per gallon · Per person = Cost ÷ people

Worked example

A 300-mile trip in a 30 MPG car at $3.50/gal: 300 ÷ 30 = 10 gallons × $3.50 = $35. Split 4 ways = $8.75 each.

Planning trips and comparing vehicles

Fuel is often the biggest variable cost of a road trip, and this makes it concrete. It's also useful for comparing vehicles: the same 300-mile trip costs $35 at 30 MPG but $52.50 at 20 MPG — a difference that compounds over a year of driving. The calculator handles metric too (L/100km and price per litre). For the flip side — measuring your car's actual MPG from fill-ups — use the gas mileage calculator, and for a car purchase's total cost, the auto loan calculator.

Frequently asked questions

How do I calculate the fuel cost of a trip?

Distance ÷ MPG = gallons; × price per gallon = cost. 300 mi at 30 MPG, $3.50/gal = $35.

How can I split fuel costs?

Divide total cost by the number of people — enter passengers to see per-person cost.

Does this work for a round trip?

Yes — enter the total (round-trip) distance.

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Last reviewed: July 2026.