⛽ Road Trip Gas Cost Calculator

Gallons first, then dollars, then stops

Distance divided by fuel economy gives the fuel you burn; the rest follows from it. Fill-ups round up, because a partial tank is still a stop:

gallons   = distance / mpg
cost      = gallons × price per gallon
fill-ups  = ceiling(gallons / tank size)

The defaults - 600 miles at 30 mpg and $3.50 - need 20.0 gallons, cost $70.00 and take 2 stops with a 14-gallon tank. Enter the round-trip distance if you are coming back: 1,200 miles is $140, not $70.

What eats the mpg you typed in

• Speed, more than anything. Above 50 mph each extra 5 mph costs roughly 7% of your mileage. Cruising at 75 instead of 65 turns 30 mpg into about 26 and this trip into $80.
• Anything on the roof. A cargo box costs 10-25% at highway speed. Bikes on a hitch rack cost far less than the same bikes up top.
• Use your own average, not the window sticker. EPA highway figures assume 48-60 mph unloaded; a full car, a headwind or a mountain pass all pull it down.
• The tank estimate assumes empty to full. Most people refill near a quarter tank, so treat 14 gallons as about 10 usable and add a stop on long legs.

Frequently asked questions