๐ Automotive
Compression Ratio Calculator
Compression ratio is the swept volume plus the clearance volume, divided by the clearance volume. A typical naturally aspirated petrol engine runs 9:1 to 11:1, and going much higher requires higher-octane fuel to avoid detonation.
How it works
Bore
Stroke
Clearance volume per cylinder
Number of cylinders
Target compression ratio
Swept volume per cylinder
Total displacement
Compression ratio
Clearance volume for your target
Fuel recommendation
Frequently asked questions
How do I use the Compression Ratio Calculator?
Fill in the fields above โ the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.