Battery CCA Sizing Calculator
Pick the correct cold-cranking amps for your engine displacement and climate. Battery replacement is one of the most common car repairs — get the right CCA the first time and avoid winter no-starts.
CCA (Cold Cranking Amps) Calculator
Match battery CCA rating to your engine size, fuel type and climate.
How It Works
Battery group size (24F, 35, 65, 75, 78, H6, H7, H8) determines physical fit. CCA rating determines starting performance. Both must match — wrong group size won't fit, wrong CCA leaves you stranded on cold mornings.
How to Use This Calculator
- Look up your battery group size from the owner's manual or current battery label.
- Enter engine displacement and your typical winter low temperature.
- The calculator returns minimum CCA and recommended CCA.
- Buy a battery in your group size at or above the recommended CCA.
Worked Example
Reference Table
Common North American battery groups, typical applications, and CCA ranges. Use BCI group designations — European cars often use ETN or DIN sizes that overlap with H5/H6/H7/H8.
| Battery group | Common applications | Typical CCA range |
|---|---|---|
| Group 24/24F | Honda, Toyota midsize | 550–700 CCA |
| Group 26/26R | Honda Civic, older imports | 520–650 CCA |
| Group 35 | Subaru, Toyota, Nissan | 550–720 CCA |
| Group 47/H5 | Volkswagen, BMW small | 600–700 CCA |
| Group 48/H6 | BMW 3-series, Audi A4 | 700–800 CCA |
| Group 49/H8 | Mercedes E-Class, large luxury | 750–900 CCA |
| Group 65 | Ford F-150, Lincoln | 650–850 CCA |
| Group 78 | GM trucks, SUVs | 700–900 CCA |
| Group 31 | Diesel trucks, RVs | 900–1150 CCA |
Frequently Asked Questions
What does AGM mean?
Absorbent Glass Mat — a sealed lead-acid design that handles deep discharges and high cranking loads better than flooded batteries. Required on most stop-start vehicles. Costs 50–80% more than flooded but lasts 30–50% longer.
Is a higher reserve capacity worth it?
Reserve capacity (RC) measures how long a battery can run essential loads after the alternator fails. Important for off-road, accessory-heavy, or trailer-towing builds. For commuter cars, CCA matters more.
How do I know which battery group fits my car?
Check the owner's manual or measure your current battery (length × width × height). Battery vendors' websites have a "find my battery" tool by year/make/model.
Can I install an AGM battery in a car that came with flooded?
Yes, AGM is a drop-in upgrade as long as the group size matches. Most modern vehicles don't require a charge-control reprogram, but BMW, Audi, and Mercedes do — they need a battery registration via OBD.
How often should I replace my car battery?
Every 3–5 years for flooded, 4–7 for AGM. Replace early if you notice slow cranking, headlights dimming at idle, or the battery age indicator on the top label shows over 4 years.
