For macOS
Find what's
draining your Mac
Get your battery back. Which app is draining your Mac right now, in watts, and how many minutes you get back if you quit it. A live reading, not a report on yesterday.
10 days free, no card. Notarized by Apple. Requires an Apple silicon Mac and macOS 14 or later.
Battery health (capacity, cycles, temperature) is free, and stays free when the trial ends.
Or from the terminal:
brew install --cask wattmateapp/tap/wattmate
2 minutes after you quit an app, while you're on battery, WattMate measures the Mac again and prints what actually changed.
The problem
macOS can rank your apps.
It can't say what you get back
macOS · Activity Monitorthe tool that comes with your Mac
If I quit Safari, what do I get back?
42.3
Safari's Energy Impact. It has no unit, so it can never become minutes. You can rank apps with it, and that is all.
WattMate
If I quit Safari, what do I get back?
24 minutes of battery
2 hr 34 → 2 hr 58
Safari is drawing 7.0 W of the 31.0 W the Mac uses right now: a quarter of everything.
In the menu bar
One click. Everything that's
using power, in watts
Real watts, not a score
Two things here are measured, not guessed: how fast the battery is losing energy, and how much energy the chip is using. The first comes from the battery's own current and voltage; the second from the counters inside the chip.
Minutes, not percentages
A share tells you how the pie is cut. A minute tells you what quitting an app is worth. WattMate takes the time your Mac says is left and shows what it becomes without that app.
Its helpers count too
A browser is thirty processes and a compiler spawns hundreds that live for seconds. They're grouped with the app that started them, so the number next to the name is the whole app.
Overnight
macOS keeps the list
and shows it to nobody
Every wake-up is logged
with the name of whatever asked for it, not powerd or
dasd, which only carry the request, but the app behind it. We read
that log and print the names, with how often each one woke your Mac and for how
long it held it awake.
One Mac, one night: fourteen percent over eleven hours, and the two hours that took more than half of it: a phone charging from the sleeping Mac. Yours will read differently. On the second Mac we measured, the wake-ups were ten times as frequent and a ninth as long. What each wake-up cost we don't know (macOS reports charge in whole percent), so we say how many times and for how long, and nothing more.
Plugged in
When the adapter
can't supply enough
Plugged in and still losing charge? That happens when the Mac needs more than the adapter delivers. WattMate says so in watts: the Mac needs 71, the adapter gives 59, and the missing 12 come out of the battery.
It also shows where those watts are going, app by app, and the two things that fix it. macOS shows none of this: it shows a battery icon that stops filling.
The one number
When one app is worth naming, it is
a quarter of everything the Mac uses
26%
Measured, split by model
of the whole Mac goes to the top app in the moments when there is something to name. That is the median across 308 such moments of real work.
+28
Projection
minutes back if you quit it, at two hours remaining. A quarter of those moments were worth +16 or less; a quarter, +60 or more.
2.6×
Measured
between a light hour and a heavy one: 4 hr 02 from a full charge against 1 hr 33. What you're doing decides it, not the battery.
The receipt
A promise you can check
Any tool can print a number. 2 minutes after you quit an app, WattMate measures the Mac again (on battery, where power use can be measured) and prints what actually changed.
And when the load moved for other reasons over those two minutes, it says so plainly instead of taking the credit. Those quits are not counted toward your total.
The only screen where both halves stand together: what we promised before you quit, and what the Mac actually did after.
New in 1.4
One app, kept in sight
Star the app you keep an eye on, and it gets its own item in the menu bar: its icon and its watts, beside the battery. Click it and you get a verdict on the last hour rather than a number to interpret: behaving as usual, above its usual since 12:47, using power in the background, or running away.
Set a line in Settings, ten watts for five minutes by default, and WattMate notifies you once when the app stays over it. Once per spell, on battery only, and never when the figure would not be a measurement.
"Usual" is the median of the last hour, so a spike is measured against the hour it stands out from. How the verdict is decided ›
Over months
Every charge you go through
leaves a record
Detailed data is kept for two days and then deleted. The summary of each session is kept indefinitely (until you erase it yourself in Settings), a few dozen bytes that answer "where did yesterday's charge go?" long after the details are gone.
A month of sessions on battery: how long each one lasted, how much charge it cost and which apps it went to.
What we can and can't measure
The limits are printed
on the box
Graphics has a total, not an owner
Graphics energy is measured as a total. Which app used it is worked out from how long each app kept the GPU busy: macOS has no per-app energy counter for graphics. The total is exact; the split between apps is not.
The Neural Engine is never blamed
Its energy is measured, but nothing in macOS says which app asked for it. So it is never charged to an app. It stays under its own name, where you can see it.
Rounded against ourselves
Your Mac's own power isn't knowable to the watt, so the minutes are shown at the low end of what the measurement allows. You'll rarely get less than shown.
It says "Still measuring"
The app list is there from the first seconds; naming the minutes needs more measurements. The screen says exactly that, instead of showing a number that will change.
Sometimes no app is to blame
On a quiet Mac most of the power goes to the screen and to simply being awake (two thirds of it on the second of the two Macs we measure), and the apps are left with a sliver. In two sessions out of five there, so little belonged to apps that the session says exactly that: nothing here to close, instead of ranking apps that add up to nothing.
Two pages carry the rest of this: what the app measures and where it stops, and who does the measuring, on which Macs, and what happens when one of our numbers is wrong. If you came here about one specific app, the measured cost of Chrome, Xcode, Telegram, Spotify and Slack is written out window by window.
Pricing
10 days,
then decide
The whole app for 10 days from the moment you open it. No card, no account, nothing to cancel. When they are over the app keeps showing what it measures, and the minutes and the log close.
Two ways to pay for the same thing: rent it or own it. Both open every paid part; neither buys updates, because updates are not sold here: a new version works with the key you already have.
A year
$9.99
Renews yearly, cancel any time. If it lapses, the paid parts lock again and everything you measured stays where it is.
Buy
Forever
$29 $19
Launch price for the first 100 keys Paid once. The key never expires, and nothing about it renews.
Buy
The price you see is the price you pay. Where VAT applies it is already inside that number, and checkout adds nothing on top.
The trial needs no card and no account. A key activates on two Macs.
Already bought? The key arrives by email from Lemon Squeezy. In WattMate: click the menu bar icon, open Settings…, go to the Licence tab, press Bought already? Enter your key, paste it and press Activate. It works offline for a week if the network is down.
Privacy
Everything is computed
on your Mac
App names, process names and your energy history never leave the machine. There is no account and nothing to sign in to.
Anonymous usage statistics and crash reports are on by default: app version, Mac model, macOS version and counters rounded to steps, tied to a random installation id. One switch in Settings turns them off, and the privacy page lists every event by name.
0.1 W
Measured
is what the instrument itself costs: two tenths of one percent of what the Mac uses. About a minute of battery across a working day. Measured on one Mac; the cost of a single measurement tick is guarded by a test.
Questions
Why isn't this in the App Store?
Does quitting apps actually save battery?
Battery health says 96%, so why does a charge only last a few hours?
Why does my Mac lose charge overnight?
Does it work on Intel Macs?
What happens when the year runs out?
Will it be accurate on my Mac?
Does it use much power to run?
See where the hours go
10 days free, no card · Requires macOS 14 or later · Apple silicon
Or from the terminal:
brew install --cask wattmateapp/tap/wattmate