How do I calculate battery SoH from usable capacity?
A report gives a present usable capacity and an original usable capacity. How can those figures be compared, and what needs to match before the resulting percentage means anything?
EVVerity explains
A closer look
The calculation
Divide the measured current usable capacity by the original usable capacity, then multiply by 100. In a hypothetical example, 54 kWh divided by 60 kWh gives 90%. That describes a capacity comparison; it does not certify the condition of every component in the battery pack.
Match the measurement boundaries
Both figures must describe the same kind of capacity. A current usable-energy estimate divided by a gross nameplate figure creates a misleading loss. Record the source, method and date of each number. If the original usable baseline is unknown, leave the result unknown instead of filling it with the nearest model name.
Keep uncertainty visible
If current capacity is estimated as 53–55 kWh against a documented 60 kWh baseline, the arithmetic range is about 88.3–91.7%. Reporting 90.00% would hide that uncertainty. A repeatable assessment matters more than extra decimal places.
About this editorial content
Prepared with AI assistance for EVVerity. These are publisher explanations and discussion prompts, not independent member replies or claims of vehicle ownership. Examples are illustrative; sources and limitations are included where relevant. Read our editorial approach.
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