Open BatteryInfoView, look at the Battery Health row, and you will see a single percentage. Older guides — and older versions of the program itself — call a very similar number the Wear Level instead. The two are not competing measurements and they are not two separate scores. They are opposites derived from the same two capacity figures, and understanding that one relationship removes most of the confusion around laptop battery percentages.
This explainer is part of our Tutorials hub. For the step-by-step health check itself, see How to Check Laptop Battery Health with BatteryInfoView; for downloads, see the download page.
The short answer: Health = 100 − Wear
Battery Health and Wear Level describe the same loss from opposite ends:
- Battery Health (%) = Full Charged Capacity ÷ Designed Capacity × 100. It answers: how much of the original capacity remains?
- Wear Level (%) = 100 − Battery Health. It answers: how much of the original capacity has been lost?
If a battery’s health is 83%, its wear level is 17%. If health is 100%, wear is 0%. There is no third calculation hiding behind either label — both numbers come entirely from Designed Capacity (the capacity when the battery was completely new) and Full Charged Capacity (what it can hold at a full charge today), usually both shown in mWh. Our formula explainer and Designed vs Full Charged Capacity guides break those two inputs down in detail.
History: added as Wear Level in v1.05, renamed Health in v1.23
The field has been in BatteryInfoView for most of the program’s life, but under two different names. That history matters because screenshots and forum posts from different years use different labels for the same row.
| Version | What changed |
|---|---|
| v1.05 | The ‘Battery Wear Level’ field was added, calculated from Full Charged Capacity and Designed Capacity. |
| v1.23 | The ‘Battery Wear Level’ caption was changed to ‘Battery Health’, because wear level is the opposite value. |
Nothing about the underlying inputs changed in v1.23 — it was a caption change, not a new measurement. NirSoft’s official history states the reason plainly: wear level is the opposite. A guide written against v1.05–v1.22 that tells you to find ‘Wear Level’ and a guide written against v1.23 or later that tells you to find ‘Battery Health’ are pointing at the same row in the same F7 Battery Information view. The current version, v1.27 (March 2026), shows Battery Health.
This also means there is no separate current ‘wear level’ field to hunt for in v1.27. If a site lists both Battery Health and Wear Level as two present-day BatteryInfoView fields, it is describing the history as if it were the current interface — in the current program you get Health, and you derive Wear by subtracting from 100 if you want it.
How to convert between the two in your head
The conversion needs no calculator for round numbers, and only one subtraction for the rest:
- Health 100% → Wear 0% — a battery at (or reporting) its full designed capacity.
- Health 92% → Wear 8% — 8% of the original capacity is no longer available.
- Health 75% → Wear 25% — a quarter of the original capacity has gone.
- Health 60% → Wear 40% — only three-fifths of the original capacity remains.
When you compare BatteryInfoView with another tool, check which label that tool uses before comparing numbers. HWiNFO, for example, is commonly described in terms of wear; Windows’ built-in battery report shows the two capacities without computing either percentage for you. Two tools can appear to disagree by a wide margin — 83 versus 17 — while reporting exactly the same battery in exactly the same state, simply because one shows Health and the other shows Wear. Our comparisons in the Comparisons hub, including BatteryInfoView vs powercfg /batteryreport, call out the label each tool uses for this reason.
What the percentage means in everyday terms
Health is a capacity ratio, not a runtime prediction and not a safety judgement. A battery at 83% health holds about 83% of the energy it held when new at a full charge. On the same laptop doing the same work, you would generally expect proportionally shorter unplugged time than when the battery was new — but BatteryInfoView itself does not promise a runtime figure from the health percentage. Its estimated time fields (Remaining battery time, Full battery time, and the charging-time estimates) are separate calculated fields, worked out from the change in Current Capacity Value over the last 30 seconds, and they should be read as estimates for the current activity only.
Health also says nothing on its own about how the capacity was lost, how quickly it is still falling, or whether the battery has a fault. A five-year-old battery at 82% that loses a point or two a year is in a very different situation from a one-year-old battery that dropped from 95% to 82% in a month, even though today’s percentage is identical. That is why a dated, exported record helps: save your figures with Export a Battery Report (Ctrl+S) and compare over time, or watch drain behaviour with the Battery Log.
Common misunderstandings to avoid
“My wear went up, so something is broken”
Wear rising is the normal direction of travel for every rechargeable laptop battery — NirSoft’s own wording is that the health of a new battery should be around 100% and it gradually decreases. Gradual is the key word. Wear itself is not an error code.
“Health below a set number means I must replace it now”
BatteryInfoView publishes no official good/fair/poor thresholds, and this site does not attribute any threshold bands to NirSoft. As general editorial guidance, replacement becomes worth considering when the shorter runtime, or symptoms such as swelling or sudden shutdowns, interfere with your use — not merely because a percentage crossed an arbitrary line quoted on a forum. See When Should You Replace a Laptop Battery? for a calmer decision process.
“I can bring the health percentage back up”
Not with BatteryInfoView. The program only displays and logs information; it has no calibration, repair, revive, or optimisation function. Content claiming a tool setting restored lost designed capacity is describing, at best, a change in what the battery reported — not recovered physical capacity. Our guide to Laptop Battery Calibration explains what calibration can and cannot do, honestly.
Frequently asked questions
Which number should I quote if someone asks about my battery?
Quote Battery Health together with the two capacities it came from — for example, health plus Full Charged Capacity and Designed Capacity in mWh. That gives anyone helping you the full picture and avoids the Health-versus-Wear label confusion entirely.
Why do I only see Health in v1.27, with no Wear row?
Because the row was renamed in v1.23. Compute Wear as 100 minus Health if you need it for comparison with an older guide or another tool.
Does cycle count change the health calculation?
No. The calculation uses only Designed Capacity and Full Charged Capacity. Cycle count is a separate field (shown only if the battery provides it) — see How to Check Your Laptop Battery Cycle Count.
In one line to remember: Health is what remains, Wear is what is gone, and they always add up to 100. Return to the Tutorials hub or run the check yourself from the download page via the official file at /go/batteryinfoview.