One app, kept in sight
Updated 20 September 2026 · every wording quoted here is the text the app actually shows, taken from its own strings file. New in 1.4. Who measures this.
Most people have one app they keep an eye on: the one they are building, the one that surprised them last week, the one that is not supposed to be doing anything right now. Star it, and WattMate keeps it in the menu bar with its watts, answers "is this normal?" when you click, and tells you when it stops being normal.
The item sits beside the battery. Click it and the panel opens with a verdict on the last hour, not a number to interpret.
What it looks like
A star on the app's row in the list, or on its page. From then on the app sits first in the list whatever it uses, and gets its own item in the menu bar: its icon and its watts, the same figure the row prints, rounded the same way. When the app is closed the item dims and shows a dash rather than a stale number. The item is a switch in Settings ("Show the favorite app in the menu bar"), and it can be dragged out of the menu bar like any other.
Click the item and a panel opens. Its first line is a verdict about the last hour, the second is the reason, and under them the hour itself: forty bars of ninety seconds each, with the app's usual level drawn across them as a dashed line. "Usual" is the median of that hour, not the average, so a twenty minute spike does not move it much. That is the point of a median: it is what the spike is measured against.
The verdict
There are nine outcomes, and the order matters: the app checks the loud ones first. Eight are here; the ninth, a phone charging from the Mac, has a section of its own below.
| Situation | What the app says |
|---|---|
| The threshold you set is crossed | "Running away: 13.5 W for the last 7 min" · "over 10 W for longer than 5 min · notified at 14:05" |
| Higher than its usual, and holding | "Above its usual since 12:47" · "for 18 min now" |
| Higher than usual while you were not using it | "Using power in the background" · "its window has not been active for 40 min, yet it uses more than usual" |
| Within the usual | "Behaving as usual" · "no spikes in the last hour" |
| Higher right now, but only just | "Behaving as usual" · "higher right now, too briefly to call yet" |
| Too early to know what is usual | "Still measuring" · "too few readings yet to know what is usual for it" |
| The app is closed | "Closed" · "the last hour ends where it closed" |
| The Mac is on power | "On power" · "measured on battery · the last hour ends where the cable began" |
"Above its usual" needs one and a half times the median, held for at least three bars in a row. One bar over is a spike, two is a coincidence; the verdict does not go orange on either. A "new peak" is named when the hour's highest bar is less than ten minutes old, because that is an event; an hour-old peak is a fact and sits under the ribbon instead.
The notification
In Settings, under Notifications: "Tell me when the favorite app goes over", with two numbers, "Above" so many watts and "For longer than" so many minutes. Ten watts for five minutes by default. The rule is the same one the panel prints: every window in the trailing run must be above the line, the run must cover the whole threshold, and the newest window must be fresh. A run interrupted by sleep or a cable starts over.
The notification reads "Xcode is using 13.5 W", then "Above 10 W for 7 min now. Open the panel to see what it has been doing." It comes once per spell: the app has to fall back under the line before it can ring again. It never comes on power, because on power the number it would quote is not a measurement of the battery.
What it says when it cannot say
While a phone charges from the Mac, the item shows a dash and the panel says why: "the cable hides what apps use · the last hour ends where the cable began". The phone's current sits inside the machine's draw and leaves no trace on the chip, so any per-app figure in that hour would be inflated by it. The ribbon stops where the cable began, and if the whole hour went that way the panel says so: "the last hour was spent with a phone on the cable".
On power the panel does not judge. It still draws the hour up to the cable, and it still says "usually" from the battery windows it has, but the watts of the moment come from a different instrument, and comparing one against the other would call an app "above its usual" at the exact moment you plugged in.
What this does not do
One app at a time, on purpose. Two stars would mean two items in the menu bar and two panels, and the feature would turn into the list it was meant to spare you from. Starring a second app moves the star.
Nothing here exists in the App Store edition, and not as a temporary gap: the sandbox forbids asking the system about other processes, so there is no per-app list to star from. The features page says the same about the list itself.
The hour is measured on battery only. Windows are written while the Mac runs off the battery, because that is where power use can be measured; on power the ribbon shows what was recorded before the cable, and nothing after it.
Questions people ask
Why a verdict and not a chart?
Because a chart makes you do the judging. The thread this came from said it in one line: "a menu bar number only tells you something is growing, not why". The panel answers the first half, whether it is growing beyond its usual, and hands the second half to the app's page and to Instruments.
How long before it knows what is usual?
Six bars, nine minutes on battery. Until then the verdict says "Still measuring", and no time is promised, because the warm-up length is a median, not a guarantee. The threshold notification does not wait for that: it has a line of its own.
Does the item drain anything itself?
The item reads the same list the popover keeps, rebuilt each time a window completes, and on power it keeps that list alive the way an open popover does. Its own cost has not been measured separately yet, so this page does not put a number on it.
Related: watts per app · the quit receipt · what each app actually costs · how we count