What do battery degradation percentages mean in daily use?
A State of Health reading like "93%" is accurate but abstract — it doesn't tell you, on its own, whether you'll notice anything different behind the wheel. Translating the percentage into real-world range and charging numbers is what actually matters when you're deciding whether a car's battery condition is acceptable for how you plan to use it.
From percentage to kilometres
Range loss scales roughly in proportion to SoH loss. It won't be exact, because range is also affected by weather, driving style, and tyre choice, but it is a reliable rule of thumb for comparing a used car's likely range against its original spec.
| Original real-world range | Measured SoH | Realistic range today |
|---|---|---|
| 400 km | 97% | ~388 km |
| 400 km | 93% | ~372 km |
| 400 km | 85% | ~340 km |
| 400 km | 78% | ~312 km |
Charging time and speed
Charging is affected too, though less directly. A battery with lower SoH generally still accepts a fast charge, but the usable window — the amount of energy it can actually take on above 0% and below 100% — is smaller, so a fast-charging stop delivers less real range added per session even at the same charging speed. This mostly matters for drivers who lean heavily on public DC fast charging for long trips.
Where you'll actually notice it
| Trip type | Practical impact of moderate degradation |
|---|---|
| Daily city commuting | Essentially none — a 30 km round trip barely dents even a reduced range |
| Mixed daily driving with occasional longer trips | Minor — one extra top-up charge on longer days |
| Regular long motorway trips near the car's range limit | Noticeable — fewer km between charging stops, more planning required |
| Towing or heavy loads | Compounds with degradation, since both reduce effective range |
Why this matters for a report
This is exactly why a Battery Truth report translates the raw SoH percentage into an estimated real-world range and a plain description of what that means for typical trips and long-distance driving, rather than leaving you to do the maths from a single number.
How long does it take to reach these percentages?
Geotab's 2026 fleet analysis found an average annual degradation rate of 2.3% across 22,700 EVs. At that average rate, reaching 93% SoH takes roughly 3 years and reaching 85% takes roughly 7 years — though, as covered in our degradation guide, the actual rate for a specific car depends heavily on climate, charging habits, and usage.
Related guides
What is State of Health (SoH)? Everything about your EV battery's condition
SoH measures how much usable capacity your EV battery retains compared to when it was new. Here's what the number actually tells you, how it's measured, and what counts as good.
Read moreExplanationHow EV batteries degrade over time
Age, mileage, and charge behaviour all play a role. Here's what the data actually shows about how — and why — EV batteries age.
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