Battery Atlas

Vehicles, trucks & marine

Cold Cranking Amps (CCA) Calculator

Estimate an orientative minimum CCA from engine displacement and compare it with your battery. The vehicle manufacturer's specification always takes priority.

Results are mathematical estimates from the values you enter — not measurements and not data about a specific product or vehicle.

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Formula

ci = L × 61.024
CCA(min, orientative) ≈ ci × k   (k = 1 gasoline, k = 2 diesel)
margin = CCA(battery) − CCA(required)

Worked example

2.0 L gasoline = 122 ci → ≈122 CCA orientative minimum. Most modern vehicles specify considerably more; use the OEM figure when available.

Limitations and warnings

  • The 1 CCA/ci (gasoline) and 2 CCA/ci (diesel) rule is an industry rule of thumb, not a standard. It ignores compression ratio, oil viscosity, starter design and electrical loads.
  • CCA cannot be converted to Ah (or vice versa) with a universal formula: they measure different things (cranking current vs stored charge).
  • SAE, EN, DIN and JIS ratings use different test conditions, so their numbers are not directly interchangeable.

Four values that are often confused

Nominal capacity (Ah)
Charge a battery delivers under rated conditions, usually over 20 hours (C20) at 25 °C.
Usable capacity
The part of the nominal capacity you can use without damaging the battery — about 50% for lead-acid, 80–90% for LiFePO4.
Cranking current (CCA)
Current deliverable for a short time in the cold to start an engine. It measures power, not stored charge, and cannot be converted to Ah.
Stored energy (Wh)
Ah × voltage. The right unit to compare batteries of different voltages.