Finance

Fuel Trip Cost Calculator

Compute how much fuel a trip burns in dollars (or euros, reais), supporting MPG, km/L and L/100km.

Trip distance

Distance unit

miles km

Vehicle fuel economy

Economy unit

Fuel price

Price per

gallon litre

Total trip cost

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Fill in distance, economy and fuel price.

What does this calculator do?

It estimates how much fuel a road trip will burn and how much that costs in your local currency. It works in both US units (miles, MPG, gallons) and metric units (kilometres, km/L or L/100km, litres) and converts internally so you can mix and match. Knowing the real fuel cost lets you compare driving versus flying, decide whether to take the highway or a back road, or split fairly with carpoolers. The calculator also gives you a cost-per-mile figure, which is the only honest way to compare two cars: a car with 35 MPG that costs $0.10 more per gallon to fill is still cheaper to drive than a 25 MPG car at base price.

How to use the calculator

Enter the trip distance and pick miles or kilometres.
Enter your vehicle’s fuel economy in MPG, km/L or L/100km — whichever is on your dashboard or owner’s manual.
Enter the current fuel price per gallon or per litre.
Read the total cost and the cost-per-mile/km. Use the round-trip number if you need to come back.
For real-world trips bump the fuel burned by 5–10% — EPA numbers are optimistic.

How the math works

Distance is converted to kilometres. Economy is normalised to km/L. Total fuel = distance / economy, then converted to gallons or litres to match the price unit.

Total Fuel = Distance / Economy

Total Cost = Total Fuel × Fuel Price

Fuel economy unit conversions

Quick reference — MPG (US gallon) to metric.

MPG (US)	km/L	L/100km
20 mpg	8.5 km/L	11.8 L/100km
30 mpg	12.8 km/L	7.8 L/100km
40 mpg	17.0 km/L	5.9 L/100km
50 mpg	21.3 km/L	4.7 L/100km

Frequently asked questions

MPG or km/L — which should I use?

Whichever your dashboard shows. The calculator converts internally so the result is the same.

What’s the difference between US and Imperial gallon?

1 US gallon = 3.785 L; 1 Imperial gallon (UK) = 4.546 L. The calculator uses the US gallon. UK drivers should use km/L or L/100km instead.

Does this work for electric vehicles?

Not directly. EVs use kWh per mile and ¢ per kWh. Convert mentally: 30 kWh/100mi at 12¢/kWh ≈ $3.60/100mi.

How accurate is EPA / WLTP fuel economy?

Real-world consumption is typically 10–20% higher than the sticker, especially in city traffic or with the AC running.

What about diesel vs. gasoline?

Diesel costs more per gallon but typically delivers 25–30% more miles per gallon, so cost-per-mile is usually lower.

Can I split the cost with passengers?

Sure. Take the round-trip total and divide by the number of seats occupied. Some carpoolers add a small wear-and-tear surcharge — typically $0.10–0.20 per mile.

Fuel Trip Cost Calculator