EV Battery Degradation Estimator
Estimate how much battery capacity a used EV has lost based on its age and miles.
How EV batteries lose capacity
Every EV battery loses some capacity over time, from two sources: calendar aging (just sitting around, which depends on temperature, state of charge and battery chemistry) and cycle aging (every time you charge and discharge it). This calculator uses the average rates from large public datasets (Geotab, Recurrent and others) to give you a ballpark figure.
Worked example
A 5-year-old EV with 60,000 miles: 5 × 1.8 = 9% from age, plus 60 × 0.025 = 1.5% from cycling, for a total of about 10.5% lost — roughly 89.5% remaining capacity.
What this can't tell you
Real degradation varies enormously by model, climate, charging habits and battery chemistry. Two identical cars can be 10 percentage points apart at the same age. Treat the result as “rough ballpark,” not a measurement.
- LFP batteries (newer Tesla base models, BYD) degrade roughly half as fast as the older NMC chemistry.
- Hot climates (Phoenix, Texas, southern Europe) accelerate degradation noticeably.
- Heavy DC fast charging only modestly speeds it up — modern thermal management has narrowed this gap.
- Sitting at 100% in heat is harder on batteries than driving them.
Warranty floor
Most manufacturers warranty the battery to retain at least 70% of capacity for 8 years or 100,000 miles, whichever comes first. If your battery drops below that in the warranty window, you can claim a replacement (terms vary by maker).
To get a real number for a specific used EV, use a third-party report (Recurrent), an OBD scan tool, or simply do a 100–0% range test yourself in mild weather.
Frequently asked
How accurate is this estimate for my specific car?
It is a fleet-average estimate. Two identical cars can be 5–10 percentage points apart at the same age and miles depending on chemistry, climate, and charging habits. Use it as a rough planning figure — for a real number, get a Recurrent report, run an OBD scanner, or do a 100→0% range test in mild weather.
What is the typical EV battery degradation curve?
Most EVs lose 1–2% per year from calendar aging plus a small additional fraction from mileage cycling. At 5 years and 60,000 miles, expect about 88–92% remaining. At 10 years and 120,000 miles, expect 78–85%. The curve flattens after the first few years.
Does DC fast charging accelerate degradation?
Modestly. Modern EVs with active thermal management have largely closed the gap — fleet data suggests heavy DC fast users degrade only a few percentage points faster than home-charged equivalents. The bigger killer is sustained heat: leaving the car at 100% in 100°F is harder on the pack than fast-charging it.
What does the 70% warranty floor mean?
Most US EV battery warranties guarantee the pack will retain at least 70% of original capacity for 8 years or 100,000 miles. If your battery drops below that inside the warranty window, the manufacturer replaces it at no cost. Out-of-warranty replacement is rare — typically under 2% of EVs need one in the first 10 years.
How can I slow battery degradation?
Five habits: set daily charge limit to 80–90%; plug in at 20%+ rather than 5%; use DC fast sparingly (road trips fine, daily commute avoid); park in shade or a garage in hot climates; avoid back-to-back fast charges in extreme heat. None of these are required — EVs are designed for normal use — but they extend life.