Created By : Vipul Patel

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 02, 2025


Our easy-to-use boat propeller calculator tool calculates the propeller pitch, engine gear ratio, engine revs, boat speed, propeller slip. All you need to do is give any of these 4 variables as input and click on the calculate button that gives you answers in seconds. You can also find answers regarding this concept through different calculators like boat propeller pitch calculator or boat prop pitch calculator,  outboard propeller calculator or propeller calculator outboard, sailboat propeller calculator, and  propeller slip calculator.

Choose an Option
Engine Revs
Gear Ratio
: 1
Propeller Pitch
Propeller Slip
%
Unit of Boat Speed

How to Find the Boat Propeller?

Propeller slip delivers an indication of the efficiency with which a ship is traversing through the water. However, it is not to be confused with propeller efficiency.

A propeller slope can be understood by viewing the action of a screw. The pitch indicates the length that each rotation contributes to the extent to which the boat moves along on each rotation.

The gear ratio defines the number of drive shaft revolutions per propeller revolution. As such, if an engine has a gear ratio of 2:1, the machine drive shaft will turn twice for every propeller circle.

V = [RPM x PP x (1 − (PS/100))] / [GR x C]

PP = [V x GR x C] / [RPM x (1 − (PS/100))]

RPM = [V x GR x C] / [PP x (1 − (PS/100))]

PS = [1 − (V x GR x C) / (RPM x PP)] x 100

GR = [RPM x PP x (1 − (PS/100))] / [V x C]

Where:

V = speed 

RPM = crankcase speed (rpm).

GR = number of revolutions the crankshaft needs to produce one revolution of the prop shaft.

PP = blade pitch (inches).

PS = index (as a percentage).

C = constant to convert inches-per-minute of revolution to boat speed V.

V (in mph), C = 1056.

V (in knots), C = 1215.2.

V (in kph), C = 656.

Follow the guidelines that are given below to calculate the boat propeller calculator easily.

  • Take the inputs from the given problem and look into the problem what to find.
  • Apply the formula which you need and substitute the values in it.
  • Simplify the answer and you will get the answer easily.

onlinecalculator.guide is the best website that offers all math calculators that gives you instant results along with the concepts easily.

FAQs on Boat Propeller Calculator

1. How to use this boat propeller calculator?

Simply give the inputs in the input fields and click on the calculate button that gives you the answer effortlessly.

2. What is the best tool to calculate boat propeller?

The boat propeller calculator is the best online tool that calculates the boat propeller.

3. What is the best website that offers a boat propeller calculator?

onlinecalculator.guide is the best website that offers a boat propeller calculator.