semkuGas cost calculator
Enter distance, fuel economy and fuel price to estimate the trip's fuel cost.
Measured fuel economy
Based on the distance and fuel used for this journey; costs cover fuel only.
Convert distance and volume with the Measurement converter.
Calculation rules
Fuel needed is distance / mpg, distance × L/100 km / 100, or distance / km/L after matching units; fuel cost is fuel needed × your entered unit price. Round trip doubles the distance, cost per person divides by the entered people, monthly cost multiplies by the entered trip count, and yearly cost is monthly cost × 12.
One mile is exactly 1.609344 km and one US gallon is exactly 3.785411784 L; mpg uses US gallons. Calculate before rounding each displayed fuel amount, cost and converted fuel-economy value once to two decimal places, with ties away from zero; each person's share is rounded separately, so the displayed shares may not add up to the trip total.
Fuel prices are entered by you; the calculator does not retrieve live or average prices, and optional monthly totals stay hidden when no trip count is entered.
This distance-and-fuel-economy estimate does not model idling, traffic or route elevation and includes fuel cost only.
Measured fuel economy uses the distance driven and fuel used over the same journey. For fill-up records, fill the tank to the same full level both times and use the fuel added at the second fill-up. Gallons are US gallons, not imperial gallons. Round trip, people and trips per month apply only to the trip calculator. Leave the price blank to hide costs; enter 0 for a fuel cost of $0.00. Use in trip calculator transfers the unrounded fuel economy, even though the displayed value has two decimal places.
Frequently asked questions
- How much fuel and money does a 420-mile trip take at 28 mpg and $3.50 a gallon?
- One way uses 15.00 US gal, or 56.78 L, and costs $52.50 with those inputs.
- Can I mix kilometers, mpg and a price per liter?
- Yes. Distance, fuel economy and price units are converted before calculating; mpg always uses US gallons.
- What should I enter for a round trip?
- Enter the one-way distance and choose Round trip; each trip in the optional monthly count then includes both directions.
- Why do four shares of $13.13 exceed a $52.50 total?
- Each exact share is $13.125 and rounds to $13.13, so the displayed shares add to $52.52 while the trip total remains $52.50.
- How do I measure fuel economy from fill-up records?
- Fill the tank to the same full level twice. Enter the distance driven between those fill-ups and the fuel added at the second fill-up. The calculation assumes that this fuel replaces the amount used over that distance.
- Does mpg use US or imperial gallons?
- This calculator uses US gallons. One US gallon is exactly 3.785411784 liters. If your fuel record is in imperial gallons, convert it to liters before entering it.
- Do I need to enter a fuel price?
- No. Leave the price blank to see fuel economy and fuel used without costs. Entering 0 shows a fuel cost of $0.00. Example prices are sample inputs, not current market prices.
- How do I use measured fuel economy for a trip?
- Select Use in trip calculator to enter the unrounded fuel economy in the trip calculator’s selected economy unit. Your trip distance, fuel price and other trip settings stay as entered.
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Calculations run in your browser without sending your calculation inputs or results to the server. See “Privacy on this page” for information about access data.