Guide

US MPG, the US gallon, and the metric switch

Fuel tools on this site default to United States units because the audience is street riders on US roads. Miles per gallon here means miles per US gallon. A US gallon is 3.785 liters. It is not the imperial gallon still quoted in some older British figures.

Range is gallons × MPG. Four gallons at 45 MPG is 180 miles. Trip fuel is the inverse: 180 miles at 45 MPG is 4.00 gallons. Both pages use the same US gallon so the pair of examples close.

What the metric switch changes

When you choose metric, you enter liters and kilometers per liter. Internally the calculator converts to US gallons and miles, runs the same multiplication, and converts the result back to kilometers. That keeps one formula in the JavaScript file. The fuel-range page also states liters per 100 kilometers, which is 100 divided by km/L.

If you have a tank marked in liters and an MPG habit from US stickers, convert the tank first or use the switch. Mixing a liter tank with MPG on the US fields will understate range.

Open the motorcycle MPG calculator for a tank, or trip fuel for a known distance.