yCalculator

EV Battery Degradation Calculator

Last updated: April 2026

Vehicle details

Battery health is usually available in vehicle settings or third-party apps such as Recurrent or ABRP.

Degradation rate

Charging habits

Battery health score

80/100

Current status

Original capacity

60 kWh (250 miles)

Current capacity

56.4 kWh (235 miles)

Capacity retained

94%

Adjusted degradation

2%/year

Projection table

YearAgeCapacityRangeAbove warranty?
20263 years94%235 milesYes
20285 years90.3%225.7 milesYes
20307 years86.7%216.8 milesYes
20329 years83.3%208.2 milesYes
203512 years78.4%195.9 milesYes
203815 years73.8%184.4 milesYes

Warranty status

Warranty threshold: 70% capacity

Estimated breach: Never within warranty

Resale impact

Current battery health impact on resale value

£0

Estimated reduction versus a comparable EV with close to full battery health.

Charging habit recommendations

Your charging habits look battery-friendly. Keep using moderate charge limits and avoid unnecessary rapid charging.

How fast do EV batteries degrade?

Most modern EV batteries degrade at approximately 1.5-2.3% per year under normal use. After 8 years, a battery degrading at 2% per year retains approximately 85% of its original capacity. Older chemistry batteries like the Nissan Leaf's degrade faster. Modern lithium iron phosphate batteries used by some manufacturers degrade particularly slowly.

What is covered by the EV battery warranty?

Most EV manufacturers warrant the battery for 8 years or 100,000 miles, whichever comes first, guaranteeing it will retain at least 70% of its original capacity. If your battery degrades below 70% within the warranty period, the manufacturer must repair or replace it.

How can I slow EV battery degradation?

The most effective steps are to avoid regularly charging above 80-90% unless you need maximum range, reduce frequent use of ultra-rapid DC charging for daily driving, avoid leaving the battery at very low charge for extended periods, and park in shade during extreme heat.

About this calculator

The EV Battery Degradation Calculator estimates how battery capacity and driving range may decline over time. It is useful for used EV buyers, owners checking warranty risk, drivers comparing charging habits, and anyone deciding whether an older EV still has enough practical range. Use this expanded guide when you need more than a quick result. It explains the assumptions behind the EV Battery Degradation Calculator, the records to gather, and the decisions the estimate can support. It is especially useful for EV owners, used EV buyers, fleet managers, and drivers checking long-term range and battery warranty risk. The strongest use of the page is scenario comparison: change one input at a time, compare the output, and keep a note of which assumption changed.

EV Battery Degradation Calculator calculation method

The calculator starts with battery capacity, current battery health, vehicle age, and charging habits. It adjusts the degradation assumption for rapid charging, frequent charging to 100%, deep depletion, and extreme heat where those inputs are selected. It then projects capacity, range, warranty threshold risk, and possible resale impact. The calculator result depends on the quality of the inputs and on the rule set or formula selected in the calculator above. For practical use, treat the output as a structured estimate: start with the core inputs, review the main outputs, then test the decision points that matter most to your situation. Key decisions include whether battery health is acceptable, whether habits may accelerate degradation, whether a used EV has enough range.

  • current usable capacity = original capacity x battery health percentage
  • adjusted degradation rate = base rate + habit adjustments
  • projected range = original range x projected battery health percentage
  • better estimate = accurate inputs + correct rule set + realistic assumptions
  • scenario difference = revised result - original result

How to use the EV Battery Degradation Calculator

  1. Enter original battery capacity and original range.
  2. Enter current battery health or estimated capacity if known.
  3. Add vehicle age and mileage where available.
  4. Select charging habits such as rapid charging and charge window.
  5. Review projected health, range, and warranty threshold warning.
  6. Run a better-habit scenario with less rapid charging or lower maximum charge.
  7. Compare the result with service records and battery warranty terms.
  8. Gather the main inputs first: original battery capacity, current health, vehicle age.
  9. Check supporting records such as battery health report and service history before relying on a final number.
  10. Enter one realistic scenario first, using conservative assumptions where the future is uncertain.
  11. Review the main outputs: current capacity, projected health, projected range.
  12. Run at least one alternative scenario so you can see which input changes the answer most.
  13. Compare the result with manufacturer warranty terms, dealer diagnostics, and independent EV inspection reports or the relevant contract, bill, statement, or professional document.
  14. Keep the calculation date and assumptions with your notes so you can revisit the estimate when rates, rules, or circumstances change.

Worked example

Used EV with 88% battery health

Input: Original range 250 miles, current health 88%.

Calculation: 250 x 88% = 220 miles before weather, speed, and accessory adjustments.

Result: The vehicle may still be practical for many journeys, but winter range and warranty threshold should be checked.

Warranty threshold scenario

Input: Battery health is projected to fall below 70% in year seven.

Calculation: The calculator compares projected health with the warranty threshold used in the logic.

Result: The owner should check warranty mileage, exclusions, and diagnostic requirements.

Improved charging habit scenario

Input: Driver reduces frequent 100% charging and rapid charging.

Calculation: Habit adjustment is reduced in the projection.

Result: Projected degradation may improve, though it is still only an estimate.

Battery health is only one range factor

Battery degradation reduces capacity, but real-world range also depends on speed, temperature, tyres, elevation, driving style, and heating or air-conditioning use.

For a used EV purchase, compare the calculator with diagnostic battery health, service history, warranty wording, and a real test drive.

What to check before relying on the result

A useful EV Battery Degradation Calculator result starts with the same evidence you would use if you were checking the answer manually. The calculator can organise the arithmetic, but it cannot know whether a payslip is final, a bill is estimated, a quote excludes fees, or a personal circumstance has changed since the last statement.

Before making a decision, compare the calculator result with the source document that controls the real outcome. For this topic, that usually means checking manufacturer warranty terms, dealer diagnostics, and independent EV inspection reports. If there is a difference between the calculator and an official statement, contract, assessment, or professional advice, treat the official document as the stronger source.

battery health report
Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.
service history
Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.
charging history
Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.
warranty terms
Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.
range logs
Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.

Inputs that usually change the answer

The most important input is not always the largest number on the form. Sometimes a date, threshold, percentage, eligibility flag, or timing assumption changes the result more than the headline amount. This is why scenario testing is more useful than a single calculation.

InputWhy it mattersWhat to double-check
original battery capacityIt feeds directly into the estimate or changes which rule is applied.Check the period, units, eligibility, and whether the figure is final or estimated.
current healthIt feeds directly into the estimate or changes which rule is applied.Check the period, units, eligibility, and whether the figure is final or estimated.
vehicle ageIt feeds directly into the estimate or changes which rule is applied.Check the period, units, eligibility, and whether the figure is final or estimated.
charging habitsIt feeds directly into the estimate or changes which rule is applied.Check the period, units, eligibility, and whether the figure is final or estimated.
original rangeIt feeds directly into the estimate or changes which rule is applied.Check the period, units, eligibility, and whether the figure is final or estimated.

How to interpret the output

The output should be read as a decision aid, not just a number. For EV Battery Degradation Calculator, the useful question is often what the result means for timing, affordability, eligibility, comparison, or next steps.

current capacity
Use this output alongside the other results rather than in isolation. A monthly amount, percentage, date, or payback figure can look acceptable until fees, timing, evidence, or eligibility conditions are added.
projected health
Use this output alongside the other results rather than in isolation. A monthly amount, percentage, date, or payback figure can look acceptable until fees, timing, evidence, or eligibility conditions are added.
projected range
Use this output alongside the other results rather than in isolation. A monthly amount, percentage, date, or payback figure can look acceptable until fees, timing, evidence, or eligibility conditions are added.
warranty threshold warning
Use this output alongside the other results rather than in isolation. A monthly amount, percentage, date, or payback figure can look acceptable until fees, timing, evidence, or eligibility conditions are added.

Scenarios worth comparing

A single estimate is a snapshot. A better approach is to save a base case, then adjust one assumption at a time. This shows whether the result is stable or whether a small change in timing, rate, usage, income, or cost creates a very different answer.

ScenarioChange one assumptionWhat the comparison shows
Base caseUse the best current evidence.Shows the result you would expect if nothing important changes.
Conservative caseUse lower income, higher cost, slower growth, or less favourable timing.Shows whether the decision still works with less optimistic assumptions.
Improved caseUse the realistic upside, such as lower cost, better rate, higher usage, or stronger evidence.Shows the potential benefit without treating it as guaranteed.

Common mistakes and edge cases

Most errors come from using the right formula with the wrong assumption. Dates can be counted differently, rates can change, official thresholds can move, and real bills or contracts often include conditions that a simple calculator cannot infer automatically.

Diagnostics differ.
Check this point before using the estimate for a payment, claim, purchase, application, employment decision, or health-related decision.
Weather affects range.
Check this point before using the estimate for a payment, claim, purchase, application, employment decision, or health-related decision.
Warranty wording matters.
Check this point before using the estimate for a payment, claim, purchase, application, employment decision, or health-related decision.
Charging habits are only part of degradation.
Check this point before using the estimate for a payment, claim, purchase, application, employment decision, or health-related decision.

Next steps after calculating

Once you have a result, write down the key assumptions and compare them with manufacturer warranty terms, dealer diagnostics, and independent EV inspection reports. If the number affects a deadline, tax return, benefit claim, employment issue, medical question, finance agreement, or major purchase, use the calculator as preparation for a more formal check.

For lower-stakes use, the next step may simply be comparing two or three scenarios. For higher-stakes use, the next step should be checking the official guidance, speaking to the relevant organisation, or getting qualified advice before acting.

Common mistakes and edge cases

  • Displayed health estimates can differ by diagnostic method.
  • Warranty thresholds often refer to capacity, not everyday range.
  • Winter range can fall even when battery health is good.
  • Battery repairs and software updates can change reported capacity.
  • Diagnostics differ.
  • Weather affects range.
  • Warranty wording matters.
  • Charging habits are only part of degradation.

Limitations and advice boundary

This calculator is general information only and is not vehicle, warranty, or financial advice. Check manufacturer warranty terms and diagnostic reports. This is general information only and is not vehicle or warranty advice. The calculator is designed to support understanding and planning, but it cannot verify documents, predict future rule changes, or account for every exception. Use it as an estimate and check the official source before acting where the result matters.

  • Use the result as an estimate and keep the source documents used for the inputs.
  • Check current official guidance, contracts, bills, statements, or professional advice where the result affects a real decision.
  • Run a conservative scenario as well as the main scenario where costs, dates, rates, eligibility, or behaviour may change.
  • Check manufacturer warranty terms, dealer diagnostics, and independent EV inspection reports for current rules, rates, definitions, and eligibility where relevant.
  • Do not rely on a single scenario where income, costs, dates, rates, usage, or health circumstances may change.
  • Keep records of the inputs used so that the estimate can be reviewed later.

Frequently asked questions

Is degradation linear?

Not always. Some batteries lose capacity faster early on and then stabilise.

Does rapid charging damage every battery?

Frequent rapid charging can add stress, but battery chemistry and thermal management matter.

What battery health is bad?

It depends on age, warranty threshold, expected use, and price.

Can battery health recover?

Displayed estimates can move after recalibration, but lost chemical capacity generally does not truly return.

Should I avoid charging to 100%?

Many EVs are happier with daily charging below 100%, but follow manufacturer guidance.

Does mileage or age matter more?

Both matter, along with temperature, charging, and battery chemistry.

Related calculators

  • EV Range Calculator
  • EV Charging Cost Calculator
  • EV vs Petrol Cost Calculator
  • Auto Loan Calculator

What does this mean?

This calculator is designed to help you understand the likely number before you make a decision or start an application.

Your result should be checked against official UK guidance, especially if your circumstances include dependants, exemptions, prior leave, or a complex immigration history.

Treat the figure as a planning tool rather than legal advice. Where the answer affects an application deadline or major payment, speak to an authorised adviser.

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