Enter the waterline length of a moving boat into the calculator to determine the estimated boat speed.

Boat Speed Formula

The following equation can be used to calculate the boat speed.

S = 10.34*(WLS/WLM)-10.34
  • Where S is the boat speed in knots
  • WLM is the waterline length when moving (feet)
  • WLS is the waterline length when stopped (feet)

To calculate boat speed, divide the waterline length when stopped by that when moving, multiply by 10.34, then subtract 10.34.

Boat Speed Definition

A boat’s speed is the velocity at which a boat is traveling based on its waterline while moving and stopping.


What is a water line length?

A water line length of a boat that is in contact with water.

boat speed calculator
boat speed formula