Fuel Cost Calculator
Planning a road trip? Enter the distance, your car's MPG, and today's gas price — get the trip's fuel cost in seconds, one-way or round-trip.
Trip cost
Tip: check your car's real-world MPG — dashboard figures are often optimistic by 10–20%.
How to use the fuel cost calculator
- Enter the trip distance in miles.
- Enter your car's fuel economy (MPG) and the current gas price per gallon.
- Tick Round trip if you are coming back the same way.
- Read off gallons needed and total fuel cost instantly.
Know the true cost before you go
Fuel is usually the biggest variable cost of a road trip, and most people wildly underestimate it — they remember the gas price but forget to divide by MPG, or they price one direction and drive two. The math is simple: distance divided by MPG gives gallons, times price per gallon gives cost. The tricky part is honest inputs. Your car's real-world MPG is almost always worse than the sticker figure — city driving, roof boxes, underinflated tires, and a heavy right foot can easily cost you 15–25%. Use your actual average from a few fill-ups (miles driven divided by gallons pumped) for the most honest estimate. Gas prices also vary enormously along a route; pricing the whole trip at your home station's price is fine for planning, but the real total lands somewhere in the middle. For EV drivers this calculator does not apply — but the same trip-math works with your cost per kWh and miles per kWh.
Frequently asked questions
How do I find my car's real MPG?
Fill the tank, reset the trip odometer, drive normally, then refill: divide miles driven by gallons pumped. Do it a few times and average — that beats the dashboard estimate.
Does it account for the return journey?
Tick the Round trip box and the distance (and cost) doubles automatically.
What about tolls, food, and hotels?
This calculator covers fuel only — the biggest variable cost. Add tolls and stops separately for a full trip budget.
Can I use it for electric cars?
Not directly — EVs need cost per kWh and efficiency in miles per kWh instead of MPG and gas price. Same math, different inputs.