# How to Calculate Compression Ratio: 11 Steps

The compression ratio of an engine will determine its performance. Generally, if the volume of the cylinder when the piston is down is greater than the volume of the combustion chamber when the piston is up, the space is calculated as the ratio of the volume. When the intake and exhaust valves are closed, the air does not come out, the piston increases, and the air-fuel mixture is compressed. Compression ratio refers to how the cylinder gap changes from when the piston is down to when the piston is up. Five factors define this equation: cylinder displacement volume, compression volume, piston dome, head gasket volume, and chamber volume. To calculate the ratio for your vehicle, you must use the formula, compression ratio = volume at bottom dead center divided by top dead center. It's not as simple as it sounds, but if you know a few key measurements, you can calculate the compression ratio.

## Steps

#### Step 10. Use the following formula to calculate the compression ratio when you have all the above measurements:

cylinder volume + compression volume + piston volume + gasket volume chamber volume.