GUIDE深度 · Deep dive
How to Calculate Fuel Cost Accurately
Fuel cost is total miles divided by MPG times price. The common errors are counting only one leg, mixing MPG and L/100km, and using stale fuel prices. Normalize units first, then multiply by round trips.
Normalize units
The US uses miles per gallon; China and Europe use liters per 100 km. One gallon is 3.785 liters and one mile is 1.609 km.
If fuel is priced per liter, multiply by 3.785 for the gallon price, or convert MPG to km/L.
Round trips and city/highway
Double the one-way distance for a round trip, then multiply by days for multi-day trips.
City MPG is usually lower; use EPA city/highway/combined values separately.
FAQ
Why is real fuel cost higher?
Traffic, AC, load, tire pressure and driving style all lower MPG.
Which fuel price should I use?
Use current prices along the route or at the destination, not months-old data.