Engine Power Requirement Calculator
This calculator gives a rule-of-thumb estimate of engine power needed to reach your target speed. Real-world results depend on load, hull condition, propeller choice, wind/waves, and installation. Use the “recommended range” as a practical guide when choosing engine size.
Use the boat’s loaded weight (fuel, water, gear, people). Brochure “dry weight” can under-estimate required power.
Used for hull speed and a speed-vs-length indicator.
Enter values and click Calculate.
Formula: Power (HP) = (Displacement (tons) ^ (2/3) × Speed³) / Hull Factor
Hull factors: 45 (displacement), 70 (semi-displacement), 100 (planing).