WhatBattery review

Updated 23 August 2026 · everything here comes from their own pages, checked on that date. We have not measured their app: our instruments are set up for ours, and running them on someone else's software would compare methods rather than products. Disclosure: WattMate is our app, and for some of the jobs below the honest answer is theirs. Who measures this.

A free, open source menu bar app that reads battery health without rounding it, shows live power in watts, and states plainly that it will never write anything to your battery. The paid tier adds per-app watts and a sleep breakdown.

What it says it does

Their own one-line description: "WhatBattery is a macOS menu bar app that shows what your Mac, iPhone, iPad and Bluetooth accessories' batteries are actually doing." The subtitle promises "Unrounded health, live power, charger performance, and a replacement forecast".

That word "unrounded" is doing real work. macOS shows a whole percentage, and the underlying figures are not whole numbers, which is the same gap our health checker exists to print.

Price and requirements

Their wording	Quoted from
"Free and open source. Pro is a £9.99 one-time purchase."	their home page
"£9.99 once, for up to two Macs. There is no subscription and purchases have a 14-day money-back guarantee."	their FAQ
"An Apple Silicon Mac running macOS 14 or later."	their FAQ

The price is in pounds on their pages and we are not going to convert it, because a converted figure would be ours rather than theirs.

Where it is genuinely better than ours

The core is free, and the source is public. Health, live watts and accessory levels cost nothing, and the code is on GitHub under MIT. A reader can check their claims by reading the implementation. We do not offer that, and it is a real advantage rather than a talking point.

It refuses to write. Their pages state the app is "strictly read-only", which rules out charge limiting by design. If you want a limiter, this is not the app, and they say so themselves rather than leaving you to find out.

Two Macs on one key. Their licence covers two machines. Ours covers one.

Where we do something different

Both apps rank apps by live watts, so that is not a difference. The difference is what happens next. Checked across their pages on 23 August 2026, the words "quit", "predict", "verify" and "minutes" do not appear in the sense of promising what closing an app would give back.

WattMate names a number of minutes before you quit something, then measures the Mac again two minutes afterwards and prints what actually changed, including the case where the effect could not be isolated. That check is the part we have not found on anyone else's pages, and it is the reason our app exists.

The other difference is architecture rather than features: they read, we also project. A read-only tool cannot be wrong about the future because it never talks about it. Ours can be, which is why it re-measures.

Who should use which

If you want	The honest pick
A free, checkable health readout	WhatBattery
Accessory battery levels in one place	WhatBattery
Source you can audit	WhatBattery
Charge limiting	Neither — macOS 26.4 does it natively
What quitting an app is worth, checked afterwards	WattMate

Questions people ask

Is WhatBattery really free?

The core is, in their own words: "Free and open source." The Pro tier is a one-time £9.99 with a stated 14-day money-back guarantee. There is no subscription on their pricing page.

Can it limit charging to 80%?

No, and this is a design decision they publish rather than an omission: the app is "strictly read-only". Since macOS 26.4, Apple silicon Macs cap charging natively anyway.

Does it work on Intel Macs?

Their FAQ states the requirement as "An Apple Silicon Mac running macOS 14 or later", so Intel machines are outside it. The same applies to us.

Do WhatBattery and WattMate overlap?

On live watts per app, yes. On battery health readouts, yes. Running both is fine — they read the same system counters and do not conflict.