Prop Slip Calculator
Boat Speed
Speed of the boat (mph or km/h).
Please enter a valid positive number.
Engine RPM
Engine revolutions per minute.
Please enter a valid positive number.
Gear Ratio
Gear ratio (engine RPM to prop RPM).
Please enter a valid positive number.
Propeller Pitch
Pitch of propeller in inches.
Please enter a valid positive number.
Use mph (uncheck for km/h)
Calculate Slip
Result
Formula:
Slip (%) = (1 - (Boat Speed / (Prop RPM * Pitch / 1056))) * 100 (for mph) or (1 - (Boat Speed / (Prop RPM * Pitch * 0.0000254 * 60))) * 100 (for km/h). Prop RPM = Engine RPM / Gear Ratio.