CCA to Ah calculator

Convert cold cranking amps (CCA) to amp hours (Ah) and back, adjusted for your battery type.

Enter a value and pick your battery chemistry to get a rule-of-thumb range.

Estimated Ah (rule-of-thumb range)

60 to 86 Ah

CCA 600, Flooded (standard) - using a 7 to 10 conversion factor.

Why this is only an estimate

CCA and Ah measure different things. CCA is the current a battery can deliver at 0 degrees F for 30 seconds, while Ah is capacity measured over a 20-hour discharge at room temperature. There is no exact formula between them - this is a rule-of-thumb estimate, useful for rough comparison, not for precise battery sizing. If you need an exact capacity, use the manufacturer's Ah or Reserve Capacity (RC) spec instead.

Trying to size a starting battery instead? Use the CCA calculator →, convert Reserve Capacity to Ah →, or look up your car's battery →

Frequently asked

How do you convert CCA to Ah?

There is no exact formula, because CCA and Ah measure different things. As a rule of thumb for a standard flooded battery, Ah is roughly CCA divided by 7 to 10 (so a 600 CCA battery is about 60 to 86 Ah). AGM and lithium batteries use slightly higher factors.

Can I convert Ah to CCA exactly?

No. Ah measures capacity over a 20-hour discharge, while CCA measures the burst of current a battery delivers at 0 degrees F. Any conversion is an estimate for rough comparison only, not for precise sizing.

What spec should I use instead for capacity?

Use the manufacturer's Ah rating or Reserve Capacity (RC) when you need real capacity. Use CCA when you care about cold-cranking power for starting an engine.