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Fuel Range Calculator

Estimate cruising range, endurance, and reserve fuel for any powerboat configuration.

Typical: 18' cc @ 22kt = 8 GPH · 25' cc @ 28kt = 16 GPH · 32' sportfish @ 24kt = 28 GPH

Reserve rule

Cruising Range

160nm

Usable fuel: 80 gal · Endurance: 6.7 hrs

Fuel Burn per Nautical Mile

0.50gal/nm

Lower is more efficient. Plan trips with this as your cost basis.

Reserve Fuel

40gal

Provides 80 nm of emergency range — use only to reach port.

How this works

Range is calculated as (usable fuel × cruise speed) ÷ fuel burn rate. Usable fuel is your tank capacity minus the reserve — the USCG minimum is 1/6 reserve, but the conservative 1/3 rule is recommended for all coastal cruising. For offshore passages, use the 1/2 reserve rule to account for unexpected weather detours and sea-state fuel penalties.

The fuel burn per nautical mile (gal/nm) is your efficiency metric. Lower is better. Modern 4-stroke outboards typically burn 0.4-0.6 gal/nm at cruise; inboard diesels 0.2-0.4 gal/nm. Plan trips with this number as your cost basis.