Need to know if your boat can outrun its own bow wave? Hull Speed Calculator tells you the maximum efficient speed for any displacement hull based on waterline length — so you stop wasting fuel pushing past physics.
Enter waterline length, beam, and displacement to instantly see theoretical hull speed in knots, mph, and km/h. The app calculates Froude number, speed/length ratio, displacement/length ratio, and whether your hull can realistically plane.
HULL SPEED CALCULATOR
Enter waterline length and displacement to calculate theoretical hull speed. Shows speed/length ratio, Froude number, and hull speed in knots, mph, and km/h.
SPEED TABLE
Reference table showing hull speeds for waterline lengths from 15 to 60 feet at speed/length ratios of 1.0 (cruising), 1.2 (fast cruise), 1.34 (hull speed), and 2.0 (semi-planing).
POWER GUIDE
HP per ton requirements by hull type: displacement (under 40 HP/ton), semi-displacement (40-100), and planing (over 100). Includes example vessel types for each category.
SPEED CONVERTER
Bidirectional speed unit conversion: knots to mph, km/h, and m/s. Enter any value and see all conversions instantly.
Built for naval architects, boat builders, and sailing enthusiasts. Works offline.