HP to CC Conversion Calculator

When dealing with small engines (motorcycles, lawn mowers, or generators) there’s a relationship between horsepower (HP) and cubic centimeters (CC).

This tool calculates CC value from HP

Enter the value of Horsepower (HP), the conversion factor (15 to 17) and the tool will provide the equivalent CC value.

🔁 CC to HP

Formula

Here’s a simple formula to estimate the CC from HP:

CC ≈ HP × 15 to 17

This formula provides a ballpark estimate. For a more accurate calculation, it’s best to consider the engine type and manufacturer specifications.

Example Conversions

• 5 HP Engine:
  5 × 15 = 75 CC (low estimate)
  5 × 17 = 85 CC (high estimate)
• 10 HP Engine:
  10 × 15 = 150 CC
  10 × 17 = 170 CC

These estimates are helpful when comparing engines, but actual performance may vary depending on engine design.

Background

While HP measures the power output, CC measures the engine’s displacement (size). However, converting between these units isn’t straightforward, as engine design and efficiency affect the relationship. In this article, we’ll explain how to estimate HP to CC conversion, explore key factors to consider, and introduce tools that help with this calculation.

What Are HP and CC?

• Horsepower (HP): A measurement of power output. One horsepower equals the force required to move 550 pounds one foot in one second. In small engines, more HP generally means more power for tasks like mowing thick grass or powering vehicles.
• Cubic centimeters (CC): A measurement of the engine’s displacement—how much air and fuel the engine can draw in during one full cycle. A higher CC generally indicates a larger engine capable of producing more power.

The Relationship Between HP and CC

There is no precise conversion formula from HP to CC because the power an engine produces depends on several factors:

• Engine efficiency
• Compression ratio
• Fuel type
• Engine type (two-stroke or four-stroke)

However, as a rough estimate, most small engines have a power ratio of:
1 HP ≈ 15 to 17 CC

This means that, for an average engine, you can assume around 15 to 17 cubic centimeters of engine displacement per horsepower.

Quick HP to CC Conversion Table (Approximate)

Factors That Affect HP to CC Conversion

Two-Stroke vs. Four-Stroke Engines

• Two-stroke engines: Produce more power per CC but are less fuel-efficient.
• Four-stroke engines: Produce less power per CC but are quieter, more fuel-efficient, and have a longer lifespan.

Engine Efficiency

More efficient engines can generate higher HP with fewer CC. Factors like the compression ratio and fuel delivery system (e.g., carburetor vs. fuel injection) can impact power output.

Fuel Type

Engines running on different fuels—such as gasoline, ethanol blends, or diesel—can produce varying power outputs, even with the same engine size.

How to Use a HP to CC Calculator:

1. Enter the HP value (e.g., 6 HP).
2. Select the engine type (two-stroke or four-stroke, if applicable).
3. Click “Calculate” to get the estimated CC value.
4. Use the result to compare engine sizes or choose the right engine for your needs.

Applications of the Converter

• Buying Equipment: Compare power ratings for lawn mowers, go-karts, or generators.
• Modifying Engines: Choose the right size for upgrades or tuning.
• Estimating Performance: Get a rough idea of an engine’s size when only the HP is known.
• Rental or Repair Services: Find replacement engines with similar power output.