Update: Wattbar 1.5 is out, and Wattbar has a page of its own: stigern.net/software/wattbar. What’s new is in the posts for 1.5, 1.4 and 1.3.
I wanted a small power meter in my Mac’s menu bar: something that shows what my Mac is using right now, and nothing else.
So I made one: Wattbar.
Wattbar sits in the menu bar and shows, live, how much power the Mac is using, how much is coming in from the charger, and how much is going into or out of the battery. It can show how much memory is in use too. Click it and a panel shows where the power goes.
See where the power goes
Click Wattbar and a small panel shows how the power flows: from the charger into the Mac, and into or out of the battery. Each flow is a glass rod as thick as the watts going through it, with slow swells travelling along it in the direction the power moves.
When power comes from two places, or goes two ways, you see both: the battery helping a charger that can’t keep up, or the charger running the Mac and charging the battery at the same time.
Prefer plain text? Set Click shows to Simple menu in Settings, or right-click Wattbar any time.
Memory too
Since version 1.2 the panel also shows how much memory (RAM) is in use, as a bar coloured by memory pressure the way Activity Monitor does it, and how much has been moved out to disk as swap. Both can go in the menu bar as well: RAM as a percentage or in gigabytes, and swap in gigabytes.
Made for the notch
On a MacBook with a notch, the right side of the menu bar fills up fast, and macOS quietly hides whatever doesn’t fit behind a « button. The first version of Wattbar kept disappearing that way. So by default it stacks each reading as a small column, the number above an icon, which fits three readings in about the space of one.
Settings
- Choose per reading: icon and value, value only, icon only or hidden
- Stacked or single line layout
- Pick the Mac icon: laptop, bolt, gauge, chip or plug
- Decimals, the “W” unit, larger text and compact spacing
- RAM usage (as a percentage or in GB) and swap in the menu bar, if you want them
- Hide the battery reading when it’s idle
- Update every 1, 2 or 5 seconds, with optional smoothing
- Launch at login
- Click shows: the power flow panel or a simple menu
Settings… is at the bottom of the panel and in the menu (⌘,). If macOS has hidden the menu bar item anyway, open Wattbar from Spotlight and the Settings window comes up.
How it measures
Wattbar reads the Mac’s System Management Controller directly, so it updates every second or two. The battery number is the battery’s own measured power, so when charging is paused, for example by a charge limit, Wattbar really shows 0.
macOS also keeps battery statistics of its own, but they only refresh every 30 to 60 seconds, which is too slow for a live meter. Wattbar only falls back to them if the live readings aren’t available. Memory is counted the same way Activity Monitor counts it: app memory, wired memory and compressed memory.
Getting started
Unzip it and drag Wattbar to Applications. It’s signed and notarized by Apple, so it opens without warnings. The first time it runs it turns on Launch at login, and you can switch that off in Settings.
- macOS 13 Ventura or later
- Apple silicon (M1 and newer)
- About 2.5 MB, no dependencies, nothing in the Dock
A note
Like FuMachine, Wattbar was written with Claude. I made it for my own MacBook and it does what I wanted, and that’s the reason it’s here. No warranty and no support promise, but if it’s useful to you too, good.
Download
Download Wattbar 1.5 from its own page, together with the changelog.
New in 1.5: the battery card fills up to the battery’s level, glass bars for the CPU and the app list, a round of bug fixes, and about a third less processor use with the panel open. More in the 1.5 post.
New in 1.4: CPU frequency, a compressed layout that fits two readings in the space of one, Settings in four tabs, and battery health and cycles on more Macs. More in the 1.4 post.
New in 1.3: a graph of the last half hour, the apps using the most power or memory, battery and charger details, notifications, and Settings in tabs. More in the 1.3 post.
New in 1.2: RAM and swap readings, a memory bar in the panel, a much lighter panel (the animation is now drawn by the graphics chip), and fixes for a panel that could jump around, get cut off or keep the keyboard focus.
New in 1.1: the animated power flow panel, and a choice between it and the simple menu.
Wattbar is free. If it’s useful to you, you can buy me a coffee ☕