Road Trip Fuel Cost Calculator
Calculate gas or fuel cost for a road trip using distance, MPG or L/100 km, and fuel price. Supports round trips, extra driving, and equal cost splitting.
Last updated: July 2026
Estimate road-trip fuel cost
Estimated fuel cost
How much will gas cost for my road trip?
For US MPG, fuel needed in gallons equals miles divided by MPG. Multiply gallons by price per US gallon. For a round trip, the entered one-way distance is doubled before any extra-driving percentage is applied.
Metric fuel-cost formula
Fuel needed = Distance in km x L/100 km / 100. Fuel cost equals liters needed multiplied by price per liter. The calculator converts MPG, km/L, gallon prices, and mile distances at full precision when other units are selected.
Should I choose one way or round trip?
Choose Round trip when the entered distance is one way and should be doubled. If your entered distance already includes the return journey, keep One way / entered distance selected.
Why use an extra-driving allowance?
A direct route may omit detours, sightseeing, route changes, or driving around the destination. The optional percentage is your own planning buffer; no value is presented as universally recommended.
Use realistic fuel economy
Your recent real-world average can be more personalized than an official rating. Speed, traffic, weather, elevation, load, air conditioning, and driving style can change actual consumption.
Frequently asked questions
How do I calculate gas cost for a road trip?
Divide miles by MPG to estimate gallons, then multiply by price per gallon. Metric units are handled automatically.
Can I use liters and kilometers?
Yes. The calculator supports L/100 km, km/L, kilometers, and price per liter.
What is the difference between US and Imperial MPG?
US and Imperial gallons have different volumes, so select the MPG system used by the vehicle rating.
Can I split fuel cost with passengers?
Yes. The optional traveler count divides fuel cost equally.
Does this include tolls or parking?
No. It estimates fuel cost only.