How do I calculate fuel cost for a round trip?

Enter the combined outward and return distance. If both legs are 150 miles, enter 300 miles. The calculator does not automatically double your distance.

Should I use city or highway MPG?

Use the rating that best describes the route, or your measured average MPG. A mixed city/highway trip usually needs a combined estimate.

Does this calculator use US or Imperial gallons?

The inputs use miles per US gallon and dollars per US gallon. Convert Imperial MPG before using it with a US pump price.

How do I split gas money when passengers travel different distances?

Add a leg whenever the passenger group changes, select the travelers sharing each leg and enter its cost inputs. Each leg is split equally between selected travelers. Include the driver if they contribute. Amounts paid are subtracted from each person's share; final transfers appear once payments match trip spending.

Can I split actual fuel receipts instead of estimating MPG?

Yes. Choose entered fuel spending in the passenger settlement workflow. Allocate fuel spending to the relevant legs, then add tolls and parking. Count only expenses included in this trip plan.

Fuel Cost Calculator for a Trip: Estimate Gas Cost

Trip milesVehicle MPGGas price ($/gal)

Estimated result$45.08

Formula distance ÷ MPG × gasoline price

Split gas costs by passenger and trip leg

Include the driver if they share costs. Add a leg whenever the passenger group changes, including the return journey. Each leg is split equally between its selected travelers.

Copies the distance into leg 1 and uses the MPG and fuel price above for all estimated legs. Other legs, passengers and payments stay as entered.

Fuel cost basisVehicle MPG (US)Gas price ($/US gal)

Travelers and payments

Enter only payments for the fuel, tolls and parking included in this plan.

Traveler 1 nameAmount paid by traveler 1 ($)

Traveler 2 nameAmount paid by traveler 2 ($)

Trip legs

Leg 1

Leg 1 milesLeg 1 tolls and parking ($)

Who shares leg 1?DriverPassenger 2

Estimated shared trip cost$45.08

Fuel, tolls and parking across 1 leg.

Each traveler's share and payments
Traveler	Share	Paid	Balance
Driver	$22.54	$0.00	$22.54 owed
Passenger 2	$22.54	$0.00	$22.54 owed

Who pays whom

$45.08 of trip spending is not assigned to a payer yet. Match payments to the total before using final transfers.

Formula Leg cost = miles ÷ MPG × gas price + tolls and parking, or entered fuel spending + tolls and parking. Divide each leg among selected travelers; subtract amounts paid. Rounding pennies go to selected travelers in listed order.

Saved plans stay in this browser. Names and entered prices are not sent with calculator analytics.

Calculate gas cost for a trip

Enter the total trip distance, expected MPG and gasoline price per US gallon. Distance divided by MPG gives gallons used; multiplying by the pump price gives trip fuel cost. Use the total distance for a round trip, not just the distance to your destination.

Worked example

For a 300-mile trip at 30 mpg and $3.50 per gallon: 300 ÷ 30 = 10 gallons, then 10 × $3.50 = $35. A 600-mile round trip with the same inputs costs $70 in fuel.

How to use the result

The first result estimates fuel only. The passenger settlement workflow below adds tolls and parking, splits each leg between its selected travelers, and accounts for who paid. Use measured or realistic combined MPG. Add a separate leg whenever travelers join or leave, and include the return journey.

Check the full budget

Check round-trip distance, MPG assumptions and passenger shares.

Sources and assumptions

U.S. EIA public gasoline price table Accessed 2026-09-05

Calculation methodology. Worked examples use the expressly stated inputs; sample prices are illustrative rather than local quotes.

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Frequently asked questions

How do I calculate fuel cost for a round trip?: Enter the combined outward and return distance. If both legs are 150 miles, enter 300 miles. The calculator does not automatically double your distance.
Should I use city or highway MPG?: Use the rating that best describes the route, or your measured average MPG. A mixed city/highway trip usually needs a combined estimate.
Does this calculator use US or Imperial gallons?: The inputs use miles per US gallon and dollars per US gallon. Convert Imperial MPG before using it with a US pump price.
How do I split gas money when passengers travel different distances?: Add a leg whenever the passenger group changes, select the travelers sharing each leg and enter its cost inputs. Each leg is split equally between selected travelers. Include the driver if they contribute. Amounts paid are subtracted from each person's share; final transfers appear once payments match trip spending.
Can I split actual fuel receipts instead of estimating MPG?: Yes. Choose entered fuel spending in the passenger settlement workflow. Allocate fuel spending to the relevant legs, then add tolls and parking. Count only expenses included in this trip plan.

Last updated 2026-10-03