CC to HP Conversion (For Small Engines)

If you've ever wondered about the relationship between engine size (measured in cubic centimeters or CC) and the power output (horsepower or HP) of various outdoor tools, you're in the right place.

This comprehensive resource will shed light on the common engine sizes found in different types of equipment, helping you make informed decisions when selecting the right tool for your needs.

You can also use the chart as a quick refernce guide if you just want to convert between CC and HP. This CC to Horsepower conversion chart aids in comparing engine performance based on power output and size.

CC to HP Conversion

Common Conversion Rule of Thumb

A common rule of thumb for small engines is that they have approximately 35 cc per horsepower. Example: 10HP = 350cc.

Average CC of Outdoor Power Equipment

  • Lawnmowers:
    • Push Mowers: Around 140cc to 190cc
    • Self-Propelled Mowers: Around 160cc to 250cc
    • Riding Lawn Mowers: Around 400cc to 800cc or higher
  • Leaf Blowers:
    • Handheld Leaf Blowers: Around 25cc to 75cc
    • Backpack Leaf Blowers: Around 40cc to 80cc
  • Chainsaws:
    • Small Chainsaws: Around 30cc to 50cc
    • Medium Chainsaws: Around 50cc to 70cc
    • Large Chainsaws: 70cc and above
  • String Trimmers (Weed Whackers):
    • Gas-Powered Trimmers: Around 20cc to 50cc
    • Electric Trimmers: Various sizes, not typically measured in CC
  • Hedge Trimmers:
    • Gas-Powered Hedge Trimmers: Around 20cc to 30cc
    • Electric Hedge Trimmers: Various sizes, not typically measured in CC
  • Generators:
    • Portable Generators: Around 1000cc (1kW) to 10000cc (10kW) or more
    • Standby/Home Generators: Varies widely, can be much larger
  • Pressure Washers:
    • Residential Pressure Washers: Around 150cc to 300cc
    • Commercial Pressure Washers: Varies widely
  • Snow Blowers:
    • Single-Stage Snow Blowers: Around 100cc to 200cc
    • Two-Stage Snow Blowers: Around 200cc to 400cc

Quick CC to HP Conversion Chart

  • 35cc = 1 HP
  • 70cc = 2 HP
  • 125cc = 3.57 HP
  • 150cc = 4.29 HP
  • 200cc = 5.71 HP
  • 250cc = 7.14 HP
  • 300cc = 8.57 HP
  • 350cc = 10 HP
  • 400cc = 11.43 HP
  • 450cc = 12.86 HP
  • 500cc = 14.29 HP
  • 550cc = 15.71 HP
  • 600cc = 17.14 HP
  • 650cc = 18.57 HP
  • 700cc = 20 HP
  • 750cc = 21.43 HP
  • 800cc = 22.86 HP
  • 850cc = 24.29 HP
  • 900cc = 25.71 HP
  • 950cc = 27.14 HP
  • 1000cc = 28.57 HP
  • 1500cc = 42.86 HP
  • 2000cc = 57.14 HP

How do I measure CC Manually?

To calculate engine displacement, you will need to know two main parameters:

  1. Bore: This is the diameter of the cylinder inside the engine.
  2. Stroke: This is the distance the piston travels inside the cylinder.

The formula to calculate engine CC is: Engine CC = (π / 4) x (Bore)^2 x Stroke x Number of Cylinders

In this formula:

  • π (pi) is a mathematical constant approximately equal to 3.14159.
  • (Bore)^2 means you multiply the bore value by itself (i.e., square it).
  • Number of Cylinders refers to the total number of cylinders in the engine.

By plugging in the correct values for bore, stroke, and the number of cylinders, you can easily determine the engine's displacement in cubic centimeters (CC).

Base HP per CC varies by engine type

Different types of engines have different performance characteristics. 35cc per HP is a baseline average for small engines commonly used on outdoor power equipment.

HP/CC Conversion Factors to Consider

The following factors can modify the horsepower value without changing the displacement, which changes the conversion ratio. It applies to all engine types, not just small engines.

  • Is the engine turbocharged?
  • Does the engine have performance parts?
  • Does the engine require performance fuel
  • Is the engine used at low altitude?
  • Is the engine performance tuned?

Answering yes to any of these questions means that the HP per cc value is likely higher than it would be on a stock engine. Conversely, if it is a stock engine that is worn or has been neglected it is likely the HP per cc value will be lower.