Electric car battery degradation comparison: read it right
Different degradation charts rank the same brands differently because they measure different things. Here is how to read one properly, and a way to estimate your own car's numbers.
Two electric car battery degradation comparisons can look completely different, because they usually measure two different things. One tracks how much of a battery's own capacity has worn away. The other tracks how a car's real range compares with the figure it launched with. Brand matters less than how the battery has been charged. Fast, hot, frequent charging wears any battery faster than gentle, cool, mostly-AC charging does.
Why the numbers you find never agree
You have looked at two or three battery degradation comparisons. The brands come out in a different order each time: one chart makes Tesla look like the safe pick, another makes it look merely average, and a third barely mentions brand at all, talking about charging habits instead.
None of these charts is wrong on its own — they usually answer slightly different questions. They use different data, over different time spans, without enough detail for you to tell which is which. That is a hard thing to buy a used EV against.
There is good news, though: the two biggest studies on this topic broadly agree once you strip brand away from behaviour. Charging power and charging habits decide how fast a battery ages, and the badge on the bonnet barely comes into it.
Why brand comparisons keep disagreeing
Two different measurements get treated as one
A "degradation" figure usually means how much of the battery's own starting capacity remains. A "range retention" figure compares today's real range with the range the car was sold on. These sound alike, but they are not the same thing. A brand that quoted a bold range on day one can show weaker range retention, even if its battery itself has worn no faster than a rival's.
What the largest degradation study found
Geotab's 2026 study covered more than 22,700 electric cars across 21 makes and models. It put the average annual battery degradation rate at 2.3%, up from 1.8% in its 2024 study. The rise was not down to worse batteries — it tracked a change in how EVs get charged. Cars that leaned heavily on fast DC charging above 100kW wore at up to 3.0% a year, while cars charged mostly on AC or slower points wore at closer to 1.5% a year. Our guide to why DC charging slows down near 80% covers the same effect from the charger's side.
Why Tesla often looks worse on range charts alone
Recurrent's 2026 report drew on more than a billion miles of real EV driving. It found the average EV keeps 97% of its range at three years, and 95% at five. Our own look at Tesla battery degradation is worth reading alongside that figure. Tesla cars, on this same measure, tended to show closer to 90% of their original rated range at three years. That is not because the batteries wore faster — Tesla's original range figures tended to run bolder than rivals' did. Cadillac, Ford, Hyundai, Mercedes and Rivian showed almost no measurable range loss over the years Recurrent tracked. Read that as a comment on how ranges were sold at launch, as much as a comment on the batteries themselves. Our wider guide to how long an EV battery really lasts covers the lifespan question this feeds into.
How to compare batteries properly before you buy
1. Work out which measurement you are looking at. A chart titled "degradation" and a chart titled "range retention" are not the same, even when they cover the same cars. Check which one you are reading before you draw any conclusion from it.
2. Weigh charging habits above brand. In every study here, how a car was charged moved the wear rate more than which badge sat on the bonnet. A gently charged car usually beats a heavily fast-charged car from the very same maker.
3. Ask for a state-of-health reading on any used EV, not just a mileage figure. Most makers' apps, or a specialist tool, can read a battery's actual remaining capacity directly. That tells you far more than age or mileage alone. Our used EV buying guide covers what else to check alongside it.
4. Ask how the car was charged, not just how far it went. A seller who mostly used slow home AC charging is a better sign than one who leaned on rapid chargers for most of the car's life, even at the same mileage.
5. Treat any single figure as a range, not a promise. Even within one study, individual cars varied a lot around the average. A used car in front of you could sit well above or below its model's typical figure. Our roundup of what driving research shows about EV battery life covers that spread in more depth.
What actually drives the difference, at a glance
| Factor | Faster wear | Slower wear |
|---|---|---|
| Charging power | Frequent fast DC charging above 100kW | Mostly AC or slower charging |
| Climate | Hot climates | Mild climates |
| Usage | High daily mileage, heavy use | Lower, steadier use |
| What it measures | Range vs a bold launch estimate | Actual capacity vs the battery's own start point |
Charging power sits at the top of this table for a reason: it is the one factor you can actually control once you own the car, unlike climate or a maker's original estimate.
Working out what this means for your own car
You can apply Geotab's rates to a real battery size. Take a common 60kWh usable pack, close to the size fitted in several family EVs. Apply the average 2.3% rate over five years, and it drops to about 53.5kWh — a loss of just under 11%. Apply the fast-charging rate of 3.0% instead, and the same pack drops to around 51.5kWh over five years, a loss of just over 14%. Charge mostly on AC at the low-use rate of 1.5%, and the same pack still holds about 55.6kWh, a loss of only 7%.
The sum behind that is simple: take the starting capacity, multiply it by one minus the yearly rate, and repeat that once for every year you plan to own the car. For the average rate, year one alone reads as 60 x 0.977 = 58.6kWh, since losing 2.3% leaves 97.7% behind. Swap in your own battery size and your own charging habits, and you get a working estimate for your car — one that beats a brand ranking that may not match how you actually drive.
When a comparison chart is not enough
Say you are buying one specific used car, not researching in general. No big study then replaces an actual state-of-health reading on that one car, because an average describes a whole population, not the car parked in front of you. If the battery still sits inside its maker's warranty, the exact capacity threshold and the years left on it matter more than any general comparison. And if a car has a known history of heavy fast-charging use, such as private hire or delivery work, treat published averages as a weak guide, and lean on a direct health check instead.
What to do next
Get a state-of-health reading before you trust any general comparison. Check how the specific car was charged over its life, not just how far it has travelled. Our guide to EV battery care covers how to protect a battery you already own. Our wider EV model guides cover the rest of what to check before you commit to a specific car.
Sources
- Geotab — EV Battery Health: key findings from 22,700 vehicle data analysis
- Geotab — press release: EV battery health and fast charging study
- Recurrent — after 5 years, EVs still hold 95% of range
- MotorFinance Online — Geotab data points to modest rise in EV battery degradation as fast charging use grows
Common questions
Why do EV battery degradation comparisons disagree?
They usually measure different things. A "degradation" figure tracks a battery's own wear against itself. A "range retention" figure compares today's range with the figure the car launched with. A brand with a bold original estimate can show weaker range retention without its battery wearing any faster.
What is the average EV battery degradation rate?
Geotab's 2026 study, covering over 22,700 vehicles across 21 models, put the average at 2.3% a year, up from 1.8% in 2024. The rise tracked heavier use of fast DC charging across the EV fleet, not a decline in battery quality itself.
Does fast charging cause more battery degradation?
Yes, on average. Geotab found vehicles relying heavily on DC fast charging above 100kW wore at up to 3.0% a year, against roughly 1.5% for vehicles charged mostly on AC or slower points. Charging habits moved the rate more than brand did in this study.
Is Tesla's battery degradation worse than other brands?
Not necessarily. Tesla vehicles have shown weaker range retention on some measures, around 90% of original rated range at three years, but Recurrent's research puts this down to Tesla's original range estimates running bolder than rivals', not to the batteries themselves wearing faster.
How do I check a used EV's battery health?
Ask for a state-of-health reading from the manufacturer's app or a specialist diagnostic tool, rather than judging by age or mileage alone. Also ask how the car was charged over its life — mostly gentle AC charging is a better sign than heavy reliance on rapid chargers.
About the author
ElectraMile EditorialEditorial desk
The ElectraMile editorial team covers charging, running costs and EV ownership for readers in the UK and US.
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