HP to CC Calculator: Estimate Engine Size from Horsepower

When shopping for an engine — whether it’s for a motorcycle, lawn mower, or go-kart — you might find yourself asking:

“If I know the horsepower, how big is the engine in cc?”

That’s where an HP to CC Calculator comes in! It gives you a simple way to estimate engine displacement when all you know is horsepower.

Let’s break it down in plain English 👇

🔁 HP to CC & CC to HP Calculator




📋 Common HP ↔️ CC Estimates

Horsepower (HP) Approx. CC
3 HP45 cc
5 HP75 cc
10 HP150 cc
15 HP225 cc
25 HP375 cc
50 HP750 cc
100 HP1500 cc

🙋 What Is Horsepower (HP)?

Horsepower is a measurement of engine power — how much work the engine can do. More horsepower usually means higher performance, like faster acceleration or stronger towing ability.

🔧 What Is CC (Cubic Centimeters)?

CC stands for cubic centimeters, and it measures the engine’s displacement — the total volume of all its cylinders. It’s a good indicator of how much air/fuel the engine can move and burn.

More CC often means a larger engine, which usually can produce more power — but not always!

🔁 Formula to Convert HP to CC

There's no exact universal formula because different engines vary in efficiency. But a common estimate used for small engines (like motorcycles, scooters, and generators) is:

CC ≈ HP × 15

This gives you a rough estimate of the engine size based on horsepower.

✅ Example

If an engine produces 10 horsepower, you can estimate its size like this:

CC = 10 × 15 = 150 cc

So, a 10 HP engine is approximately a 150 cc engine.

⚠️ Keep in Mind

This is just a rule of thumb. The actual CC required to produce a certain HP depends on:

  • Engine efficiency
  • Fuel type
  • Turbo/supercharging
  • RPM (revolutions per minute)

For example, high-performance engines might get more HP per CC, while basic engines get less.

💡 Why Use an HP to CC Calculator?

  • You know the HP rating, but not the engine size
  • You're comparing engines across brands or categories
  • You're planning a swap or modification and want a quick size estimate

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