EV Life Check

Battery Degradation
Calculator

Find out how much range your EV battery has lost — and see how it compares to average degradation over time.

01 — Select your vehicle
Select a year to begin.
02 — Enter your current readings
years
months (0–11)
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What is battery degradation?

Every EV battery slowly loses its ability to hold a full charge over time. This is called battery degradation — and it's completely normal. It doesn't mean your car is broken. It just means the battery isn't quite as capable as it was on the day it rolled off the lot.

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Why it happens
EV batteries are made of thousands of lithium-ion cells. Each time you charge and discharge them, tiny chemical changes occur inside. Over hundreds of cycles, these changes add up — and the battery gradually stores less energy than it used to.
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What it feels like
You'll notice your car shows fewer miles at a full charge than it did when new. A battery that once showed 300 miles at 100% might only show 270 miles a few years later. Your car drives the same — it just can't go quite as far on a single charge.
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How fast it happens
Most EVs lose around 2–3% of their capacity in the first year, then slow to about 1–2% per year after that. After 5 years of typical use, most batteries retain 85–92% of their original capacity. After 10 years, most still hold 75–85%.
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Warranty protection
Nearly all EV manufacturers include a battery warranty — typically 8 years or 100,000 miles — guaranteeing the battery won't drop below 70% of its original capacity. If it does, they must repair or replace it for free.
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What speeds it up
Heat is the biggest accelerant. Frequent DC fast charging, parking at 100% in hot weather, and regularly draining to near-zero all put extra stress on the cells. Batteries in hotter climates also tend to degrade faster than those in cooler ones.
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Can it be reversed?
Degradation itself can't be undone — once capacity is lost, it's gone. However, some apparent range loss is just the battery's computer losing calibration. A full charge-discharge cycle can sometimes recover a few "lost" miles by recalibrating the display.
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How this calculator works: Your EV always shows range based on your current battery level. So if you're at 78% charge and the car shows 200 miles, that means a full charge would give you about 256 miles today (200 ÷ 0.78). Compare that to your car's original EPA range when new, and you can see exactly how much capacity has been lost — that's your degradation percentage.
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Tips — slow down battery degradation
Highest impact
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Charge to 80%, not 100%
Keeping your daily charge limit at 80% is the single biggest thing you can do. Lithium-ion cells degrade faster when held at high states of charge. Save 100% for long road trips only.
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Limit DC fast charging
DC fast chargers (like Tesla Superchargers) push high current through cells quickly, generating heat that accelerates degradation. Use Level 2 home charging for daily top-ups whenever possible.
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Avoid extreme temperatures
Heat is a battery's worst enemy. Park in the shade or a garage when possible. In hot climates, avoid leaving the car sitting at 100% charge in direct sun. Cold slows the battery but doesn't permanently damage it.
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Know your warranty — use it
Most EVs come with an 8-year / 100,000-mile battery warranty guaranteeing at least 70% capacity. If your degradation exceeds that threshold, the manufacturer must replace or repair the battery at no cost. Don't ignore it.
Medium impact
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Don't drain below 10–15%
Regularly running the battery down to near-zero puts stress on the cells. Try to plug in before you drop below 15%. Think of it like never letting your phone die completely — same principle.
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Charge at home overnight
Level 1 (120V) and Level 2 (240V) home charging is gentle on the battery. Charging slowly overnight at a moderate state of charge is ideal for long-term battery health.
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Precondition before charging
Most EVs let you precondition the battery before a DC fast charge session. This warms the pack to the ideal temperature, reducing the stress of fast charging and improving charge speed too.
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Drive smoothly — avoid hard acceleration
Flooring it repeatedly generates heat in the motor and battery. Smooth, gradual acceleration is far easier on the pack over the long run — and you'll get noticeably more range per charge too.
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Pre-cool or pre-heat while plugged in
Running climate control while still connected to a charger means the energy comes from the grid — not the battery. This is especially important in hot summers and cold winters to preserve your usable range.
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Let the battery warm up in cold weather
Charging or driving hard on a cold battery causes stress. In winter, use your EV app to warm the battery before departure while still plugged in. Many EVs do this automatically when you set a departure time.
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Don't charge to 100% then sit in the sun
A fully charged battery sitting in a hot car is a worst-case combination for degradation. If you must park in direct sun, charge to 80% instead. Even a modest reduction in charge level meaningfully cuts thermal stress.
Good habits
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Use regenerative braking
Regen braking recovers energy smoothly and reduces wear on your brake pads. It also reduces the need for aggressive acceleration cycles, which is easier on the battery over time.
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Don't leave it fully charged for days
If you're going on vacation and leaving the car parked, charge to around 50% rather than 100%. Batteries stored at high charge levels for extended periods degrade faster than those stored at mid-range.
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Use scheduled charging
Most EVs and home chargers let you schedule charging to finish just before you leave. This means you're not sitting at 100% for hours overnight — the battery tops off right when you need it.
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Keep tires properly inflated
Under-inflated tires increase rolling resistance, making the motor and battery work harder on every trip. Check tire pressure monthly — correct pressure can recover several miles of range and reduces battery strain.
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Track your battery health over time
Use this calculator every few months with the same charge percentage to track trends. A sudden jump in degradation can indicate a cell issue worth addressing under warranty before it gets worse.
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Use Eco mode on long highway drives
Eco or efficiency modes limit peak power draw and soften acceleration responses. On long trips at highway speeds this reduces the sustained load on battery cells, lowering heat buildup over time.
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Keep software up to date
EV manufacturers regularly push OTA (over-the-air) updates that improve battery management algorithms, charging behavior, and thermal control. Staying updated ensures your battery is being managed as efficiently as possible.
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Avoid back-to-back fast charge sessions
Chaining multiple DC fast charges in a row without a break keeps the battery hot for longer. If you must take a second fast charge stop on a long trip, a short rest between sessions lets the pack cool down slightly.
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