Battery Health Estimator
Pick your exact model year and battery, then turn the range your car shows into an estimated state of healthbattery health percentage. Compare it with a degradation curve for your cell chemistry, project it forward and check what your warranty actually covers.
Estimated health
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Usable capacity
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vs typical
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Warranty
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Your battery today
Projected health by mileage
Your path vs a typical curve for your chemistryTips for your battery
Projection table
Every 20,000 miles at your current paceBattery reference table
Figures are approximate and gathered from the public sources below; ratings changed mid-year on several models, and options such as wheel size move the official figure. Always check your own car's documents, warranty booklet and touchscreen.
Sources
How this is calculated
- Health = displayed range ÷ (battery % ÷ 100) ÷ the EPA range of your exact version when newthe range your exact version showed at 100% when new. The range readout is the car's own estimate of remaining energy, so it is a reasonable proxy for capacity — not a lab test.
- Why not WLTP? Tesla's owner's manual says the displayed range is based on EPA-rated consumption, even on UK cars, so a brand-new UK Tesla typically shows 10–15% less than its WLTP figure. Comparing your display with WLTP would invent degradation that isn't there. The tool uses reported UK display figures where they exist, then the equivalent EPA rating, and only as a last resort an estimate from WLTP (flagged). WLTP is still shown for reference.
- Your version matters. Tesla has changed packs, cell suppliers, chemistry and official ratings many times — a 2018 Model 3 Long Range and a 2024 one start from different figures. Choosing the model year and battery fills in the original range, usable capacity, chemistry and the warranty terms of that era. Every value stays editable.
- Capacity = health × the pack's approximate usable kWh when new.
- Typical curve depends on chemistry: a quicker drop in the first few tens of thousands of miles, then a slow, steady decline plus a little calendar agingageing. The curves are fitted to published fleet figures (listed under Sources) — treat them as a guide, not a guarantee. The band around it is ±2 points.
- Your projection starts from your own reading and follows the typical slope, made steeper by daily 100% charging on NCA/NCM packs (+25%), 90% daily (+8%), DC fast charging (up to +50%, +35% for LFP) and a hot climate (+20%). Cold climates age packs slightly slower. LFP packs aren't penalised for charging to 100%.
- Warranty uses the terms of your car's era: years, a mileage cap (or unlimited miles) and whether gradual capacity loss is covered at all, compared with the car's age and your average miles per year.
Which Teslas use LFP batteries?
Why is my range lower than the WLTP figure?
Two reasons. First, the number on the screen isn't WLTP at all: Tesla calculates it from EPA-rated consumption, so a new UK Model 3 Rear-Wheel Drive rated at 305 miles WLTP showed about 272 miles at 100%. Second, WLTP is a laboratory test — motorway speeds, cold, wet weather and heating all cut real range further. This tool compares the car's own display with what the same display showed when new, so the comparison is like for like. If you know your car's figure from delivery day, type it into the range field.
Why does my range number jump around?
The battery management system estimates capacity, and the estimate drifts with temperature and how often the pack sees very high and very low charge. A swing of a few percent is normal. LFP packs in particular need regular full charges for the estimate to stay accurate. For the best reading, charge to 100% (or 90%) in mild weather and read the number right as charging finishes.
Can I make a warranty claim from this number?
No — this is an estimate. A warranty assessment uses Tesla's own diagnostics, and older Model S and X warranties don't cover gradual capacity loss at all. If your estimate is near or below the guaranteed level while still covered, book a service appointment and ask for a battery health check.