{"id":695,"date":"2026-10-10T08:52:43","date_gmt":"2026-10-10T07:52:43","guid":{"rendered":"https:\/\/stigern.net\/blog\/?p=695"},"modified":"2026-10-26T16:41:21","modified_gmt":"2026-10-26T15:41:21","slug":"wattbar-a-tiny-power-meter-for-the-mac-menu-bar","status":"publish","type":"post","link":"https:\/\/stigern.net\/blog\/wattbar-a-tiny-power-meter-for-the-mac-menu-bar\/","title":{"rendered":"Wattbar \u2013 a tiny power meter for the Mac menu bar"},"content":{"rendered":"\n

Update:<\/strong> Wattbar 1.5 is out, and Wattbar has a page of its own: stigern.net\/software\/wattbar<\/a>. What’s new is in the posts for 1.5<\/a>, 1.4<\/a> and 1.3<\/a>.<\/p>\n\n\n\n

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.<\/p>\n\n\n\n

So I made one: Wattbar<\/strong>.<\/p>\n\n\n\n

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.<\/p>\n\n\n\n

\"Wattbar
Wattbar in the menu bar: what the Mac uses, what the charger delivers, and the battery.<\/figcaption><\/figure>\n\n\n\n

See where the power goes<\/h2>\n\n\n\n

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.<\/p>\n\n\n\n

\"The
Plugged in: the charger powers the Mac, the battery is idle, and memory use sits at the bottom.<\/figcaption><\/figure>\n\n\n\n

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.<\/p>\n\n\n\n

\"Two
Left: the battery helps the charger. Right: charging while in use.<\/figcaption><\/figure>\n\n\n\n

Prefer plain text? Set Click shows<\/em> to Simple menu<\/em> in Settings, or right-click Wattbar any time.<\/p>\n\n\n\n

Memory too<\/h2>\n\n\n\n

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.<\/p>\n\n\n\n

Made for the notch<\/h2>\n\n\n\n

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 \u00ab 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.<\/p>\n\n\n\n

Settings<\/h2>\n\n\n\n
\"The
The Settings window. The preview at the top shows exactly how the menu bar will look.<\/figcaption><\/figure>\n\n\n\n