How the cost is worked out
The calculator divides the distance by your car’s fuel economy to get the gallons you’ll burn, then multiplies that by the price per gallon:
Fuel cost = (miles ÷ MPG) × price per gallon
A 300-mile drive in a car that gets 25 MPG uses 12 gallons. At $4.28 a gallon, that’s$51.41. Pick round trip and the distance doubles; add riders and you’ll see what each person owes.
Where to find your car’s MPG
Check the window sticker, your owner’s manual or the trip computer on your dashboard. The combined MPG figure is the best fit for a mix of highway and city driving. On a long interstate run, the highway figure is closer to what you’ll actually get.
Why your real cost may differ
Fuel economy drops with high speeds, heavy loads, roof boxes, towing, cold weather and long stretches of idling in traffic. Gas prices also change from state to state, so a cross-country trip rarely costs the same per gallon the whole way. Treat the result as a close estimate and add a little extra to your budget.
Ways to spend less on gas
- Keep to the speed limit. Fuel economy usually drops quickly above 50 mph.
- Check tire pressure before you leave. Under-inflated tires waste fuel.
- Pack light and take the roof box off when you don’t need it.
- Fill up before you cross into a state with higher gas taxes.
- Use cruise control on flat highways to hold a steady speed.