EV Battery Health Calculator — Capacity Estimate
Turn your range and consumption into an estimated usable-capacity band. See what the numbers can—and cannot—tell you.
Your results
Transparent by designA clearer picture starts here.
Review the example inputs, then calculate. We show the assumptions alongside your result.
Why is this an estimate?
Age, mileage and charging habits provide context. They are not enough to establish the condition of an individual battery.
Read our methodologyEVVerity estimates are informational and are not a substitute for a professional battery diagnostic or pre-purchase vehicle inspection.
See how the calculation works
Age, mileage and charging habits provide context. They are not enough to establish the condition of an individual battery.
Example: infer usable energy, then test the assumptions
With a 320 km full-charge range estimate and matching consumption of 16.5 kWh/100 km, inferred usable energy is 52.8 kWh. A chosen ±10% input sensitivity gives approximately 47.5–58.1 kWh. Compared with an original usable 60 kWh, this corresponds to about 3.2–20.8% degradation. These are example inputs, not a measured vehicle result.
Where to get useful inputs
- Find the original usable (net) capacity in documentation for the exact battery version. A gross pack figure is a different denominator.
- Use the car’s recent driving-consumption display. Record the averaging period and conditions; do not use a charger bill.
- Enter a matching full-charge range estimate. Mixing a city-based range prediction with motorway consumption can invalidate the inference.
- Keep the report date, method and vehicle details with any BMS SoH value. An evidence-confidence label does not authenticate the report.
Is this a battery health test?
No. It is a transparent estimate based on inputs you provide. The sensitivity band is chosen by you, not a statistically calibrated confidence interval. Age and mileage alone do not produce a health percentage.
Method and examples reviewed . Vehicle specifications carry their own source dates.
Methodology, assumptions & confidence →Use the estimate to choose the next question
Original EVVerity worked scenario. Inputs are illustrative, not measured vehicle results or market prices.
- Enter original usable capacity 60 kWh, full-charge range 320 km, matching consumption 16.5 kWh/100 km and sensitivity 10%.
- Keep a report showing 90% SoH in the separate reported field. The range-based central result is 52.8 kWh, equivalent to 88% of the 60 kWh baseline.
- Change consumption to 18 while holding range at 320: inferred energy becomes 57.6 kWh. Ask whether those two inputs really describe the same driving.
What the result helps you decide
A small input change moves the capacity inference substantially. The useful outcome is identifying which observation needs checking; the tool cannot turn an estimated dashboard range into a measured battery test.
Read and compare the evidence in a battery report →Example checked .
Battery SoH calculator or usable-capacity estimate?
A capacity-based ratio is current usable capacity ÷ the matching original usable capacity × 100. If a documented assessment reports 54 kWh against an original 60 kWh usable reference, that ratio is 90%. The range-based tool above instead infers energy from range and consumption and shows its sensitivity; it cannot certify that the physical battery has 90% health.
For a known current-capacity value, use the degradation calculator. For an existing diagnostic percentage, enter it as Reported BMS SoH. Preserve the report’s method and reference rather than treating these three routes as interchangeable.
| Evidence available | Use it for | Keep separate |
|---|---|---|
| Matching full-charge range and driving consumption | An estimated usable-capacity band | Diagnostic or warranty conclusions |
| Comparable original and current usable kWh | Capacity ratio and observed degradation | Future failure date |
| A diagnostic report with a stated SoH | The provider’s reported result | Independent verification by EVVerity |
How can I check a used EV battery before buying?
Start with the exact version, original usable-capacity source and complete dated battery report if one exists. Ask for charge percentage with any range screenshot and the averaging period behind consumption. A screenshot at 80% charge should not silently become the full-charge range input.
Age, mileage or a VIN alone cannot establish remaining capacity. The free estimate can organise questions for a seller; it does not connect to the vehicle or replace a suitable battery assessment. When values disagree, keep both methods visible and check the evidence before deciding what further assessment is needed.
Which battery evidence do you have?
Choose the closest description for a useful next step. This does not diagnose the car.
I have a diagnostic report
Check the vehicle match, date, method and capacity reference. Enter any reported BMS SoH separately. If the report contains a different kind of derived health score, keep its original label and ask the provider how to interpret it.
Read the report checklist →The vehicle offers an onboard health test
Use the current owner’s manual for the exact vehicle. Confirm availability, preparation and duration with the seller. A test may not be practical during a short viewing; do not improvise a full discharge or change service settings.
Compare the test methods →I only have range and consumption
Use figures from matching conditions for an initial usable-energy estimate. Confirm the original usable baseline before calculating degradation. This does not measure SoH or establish whether a warranty claim qualifies.
Estimate with a visible sensitivity band →I do not have usable battery evidence yet
Age, mileage and VIN do not establish actual battery health. Request a recent report or discuss a suitable test with a qualified provider. Ask about supported vehicles, measurement method, scope and the final price.
See UK test-price examples and booking questions →Keep the picture in focus
All tools →Read the relevant evidence
- How long do electric car batteries last?
- EV Battery Health Tests: Methods, Reports and Limitations
- EV Battery Health Test Cost in the UK: Dated Price Examples
- How to Check Battery Health Before Buying a Used EV
- EV Battery SoH Meaning: State of Health Explained
Apply this to a model
Check the model’s battery references, charging equipment and viewing checklist. Match the year and original market to the car you are considering.