Boat Fuel Burn Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the burn rate (L/h) and hours running.
- Add a reserve % for a safe amount to carry.
How it works
Fuel used = burn rate × hours; the carry figure adds your reserve percentage.
Worked example
20 L/h for 4 hours. = 80 L used.
Common mistakes
- No reserve — always carry extra for weather, current and detours.
- Using cruise burn for a trip with lots of full-throttle running.
Frequently asked questions
What's the rule of thirds?
A third of fuel out, a third back, a third in reserve — i.e. carry about 50% more than the leg needs.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.