Tool
Motorcycle MPG Calculator
Range is the fuel in the tank multiplied by the economy you enter. The default units are US gallons and miles per gallon. Reserve is a separate field, not a guess from the petcock.
Full-tank range
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When to use this calculator
Use it when you know how the motorcycle actually drinks fuel on the roads you ride, and you want miles from a known tank. The page does not invent MPG from engine size.
Reserve is the fuel you choose to treat as a cushion. If you enter 0.8 gallons on a 4-gallon tank, miles to reserve use 3.2 gallons. That is not a factory petcock specification unless you entered the same number the bike uses.
The US gallon is 3.785 liters. If you switch to metric, you enter liters and kilometers per liter. The page also states the equivalent liters per 100 kilometers.
Empty, zero, or a reserve that is larger than the tank produces a field error.
Worked tanks
The full tank is 180 miles. That is the arithmetic check for this page: 4 × 45 = 180.
Miles before that reserve are 3.2 × 45 = 144. Do you treat reserve as a hard stop, or as a reminder to start looking for a station?
4 US gallons is about 15.14 liters. 45 MPG is about 19.1 km/L. The kilometer range should match 180 miles.
Technical questions
Is this a US gallon or an imperial gallon?
US gallon. An imperial gallon is larger and would overstate range if you used it here by mistake.
Does the calculator include a reserve automatically?
No. Reserve stays zero unless you enter it. Many street tanks have no separate petcock reserve.
Why not estimate MPG from displacement?
Two twins with the same cubic centimeters can return very different tank mileage. The honest input is the MPG you already observed.