Compression Ratio Calculator

Find an engine's compression ratio.

Compression ratio (:1) 11

Formula: ratio = (swept + clearance) ÷ clearance

Step-by-step with your numbers:

1. Values used:

2. Swept (cylinder) volume = 500 cc

3. Clearance volume = 50 cc

5. Compression ratio = 11:1

Did we solve your problem today?

The compression ratio compares cylinder volume at bottom vs top of the stroke.

The math behind it

ratio = (swept volume + clearance volume) ÷ clearance volume.

500 cc swept, 50 cc clearance → 11:1.

Higher ratio?

More power/efficiency but needs higher-octane fuel.