Is this dynamic compression ratio?
No. This is static CR. Cam timing changes dynamic CR, which this page does not calculate.
ATV Calculator
ATV Compression Ratio Calculator
Estimate static compression ratio from the cylinder's swept volume and the leftover clearance volume at top dead center.
Results
Values update after you calculate. Empty or invalid inputs will not invent a number.
Enter the values and choose Calculate to see estimates.
How it works
Swept volume comes from bore and stroke. Clearance volume adds the chamber, piston dish or dome, deck height, and head gasket.
CR = (swept volume + clearance volume) ÷ clearance volume. Piston cc is positive for a dish and negative for a dome.
These results are estimates for planning only. They are not OEM specifications, safety certifications, or professional mechanical, legal, or financial advice.
Compression Ratio Calculator FAQs
How do I enter a domed piston?
Use a negative piston cc because a dome reduces clearance volume.
Why include gasket bore?
Gasket volume is a thin cylinder. Using the gasket opening is more accurate than assuming it matches the bore.
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