What this website is
CylinderBalance Lab is a browser-based utility for recording engine compression-test and optional leak-down readings. It calculates simple cylinder-to-cylinder comparisons and creates a printable worksheet. It is deliberately narrow: no account, no upload of your readings, no mechanical diagnosis and no subscription.
What this website is not
It is not a vehicle-specific factory service manual, a certified diagnostic procedure, a mechanical inspection or a guarantee of engine condition. We do not supply universal minimum PSI values or claim that a cylinder spread threshold applies to every engine. Use the engine manufacturer's service specifications and a trained professional when diagnosing a vehicle.
How the figures are calculated
Highest and lowest values are taken from the nonblank dry cylinder readings. The variation percentage is (highest − lowest) ÷ highest × 100 when the highest reading exceeds zero. Entered manufacturer limits are not looked up automatically. Wet and leak-down readings are retained separately and are not merged into one misleading health score.
How the project may be funded
The current utility is free. We may introduce plainly labeled advertising or relevant affiliate links later to support hosting. If affiliate links are added, we will disclose that we may earn a commission. No ad, affiliate or purchase is needed to use the basic worksheet.