Propeller Calculator

Size and pitch calculations for optimal performance

Quick Samples

Try these common configurations to get started

Small Outboard (25HP)

Typical small fishing boat

Sailboat Auxiliary (30HP)

Cruising sailboat with diesel

Planing Cruiser (200HP)

Fast cruising powerboat

Hull Dimensions

Enter your boat's principal dimensions

Engine Power (HP)

Engine RPM

Gear Ratio

Target Speed (mph)

Boat Length (ft)

Propeller Type

Download 500+ Boat Plans

About This Tool

The Propeller Calculator helps determine optimal propeller size and pitch for your engine and boat combination. Proper propeller selection is crucial for performance, fuel efficiency, and engine longevity.

Key Concepts:

Diameter: Affects thrust and acceleration

Pitch: Determines theoretical speed advance

Slip: Efficiency loss (10-25% normal)

RPM: Propeller rotational speed

Frequently Asked Questions

Download 500+ Boat Plans

Get access to a comprehensive library of boat plans and tutorials.

"My Boat Plans" is a collection of over 500 boat plans, from simple dinghies to larger cruisers. It includes step-by-step guides, video tutorials, and more.

Download Now

Propeller Calculator

Small Outboard (25HP)

Sailboat Auxiliary (30HP)

Planing Cruiser (200HP)

Key Concepts:

How do I choose between diameter and pitch?

What is propeller slip and is it normal?

Should I choose a 3-blade or 4-blade propeller?

How does gear ratio affect propeller selection?

Can I use this calculator for sailboat propellers?