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Marine & Boating Calculators

Fuel Range Calculator

How far you can travel on the fuel aboard, with a safe reserve held back.

Enter values

Results update as you type.

Result

Safe range

100 nm

The old rule of thirds: a third out, a third back, a third in reserve.

In kilometres
185.2
Endurance
12.5 hours
Usable fuel
150 litres
Reserve held back
50 litres
Fuel per nautical mile
1.5 L/nm
Maximum range on all fuel
133.3 nm

About the Fuel Range Calculator

How far you can travel on the fuel aboard, with a safe reserve held back.

Also known as: range on fuel, boat fuel range, endurance calculator, how far on a tank.

How to use this calculator

  1. Enter fuel aboard, fuel burn, cruising speed, reserve to keep.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

range = usable fuel ÷ burn rate × speed

Worked example

Using the values pre-filled in the calculator above:

  • Fuel aboard = 200 litres
  • Fuel burn = 12 L/hour
  • Cruising speed = 8 knots
  • Reserve to keep = 25 %

the calculator returns:

  • Safe range: 100 nm
  • In kilometres: 185.2
  • Endurance: 12.5 hours
  • Usable fuel: 150 litres