Compression Ratio Calculator
Calculate engine compression ratio based on cylinder bore, stroke, combustion chamber volume, and other parameters. Essential for engine building and performance tuning.
Step 1: Engine Specifications
Understanding Compression Ratio
The compression ratio is the ratio of the volume of the cylinder and combustion chamber when the piston is at the bottom of its stroke (BDC) to the volume when the piston is at the top of its stroke (TDC). Higher compression ratios generally increase efficiency and power output.
Step 2: Additional Parameters
About Compression Ratios
Typical compression ratios range from 8:1 to 12:1 for naturally aspirated engines. Higher ratios require higher octane fuel to prevent detonation. Forced induction engines typically use lower compression ratios (7:1 to 9:1) to prevent knock under boost.
Compression Ratio Results
Calculated Compression Ratio
Volume Breakdown
| Component | Volume | Percentage |
|---|
Engine Specifications
Compression Ratio Formula
CR = (Swept Volume + Clearance Volume) / Clearance Volume
The compression ratio is calculated by dividing the total cylinder volume (when the piston is at BDC) by the clearance volume (when the piston is at TDC). The clearance volume includes the combustion chamber volume, head gasket volume, deck clearance volume, and piston dish/dome volume.
Need Professional Engine Analysis?
Connect with our automotive experts for detailed engine building consultation, compression testing, and custom engine tuning solutions.
Get Professional Analysis