{"id":695,"date":"2026-10-10T08:52:43","date_gmt":"2026-10-10T07:52:43","guid":{"rendered":"https:\/\/stigern.net\/blog\/?p=695"},"modified":"2026-10-10T10:06:47","modified_gmt":"2026-10-10T09:06:47","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<p class=\"wp-block-paragraph\">I wanted a small power meter in my Mac&#8217;s menu bar: something that shows what my Mac is using right now, and nothing else.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So I made one: <strong>Wattbar<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">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. Click it and a panel shows where the power goes.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"717\" height=\"64\" src=\"https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-menubar-clean.png\" alt=\"Wattbar in the macOS menu bar, showing the Mac, charger and battery readings next to the standard menu bar items\" class=\"wp-image-699\" style=\"width:717px;height:auto\" srcset=\"https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-menubar-clean.png 717w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-menubar-clean-300x27.png 300w\" sizes=\"auto, (max-width: 717px) 100vw, 717px\" \/><figcaption class=\"wp-element-caption\">Wattbar in the menu bar: what the Mac uses, what the charger delivers, and the battery.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">See where the power goes<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">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<figure class=\"wp-block-image aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"824\" height=\"820\" src=\"https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-panel.png\" alt=\"The Wattbar panel: the charger powers the Mac through a glowing green glass rod, the battery is idle\" class=\"wp-image-709\" style=\"width:412px\" srcset=\"https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-panel.png 824w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-panel-300x300.png 300w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-panel-150x150.png 150w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-panel-768x764.png 768w\" sizes=\"auto, (max-width: 824px) 100vw, 824px\" \/><figcaption class=\"wp-element-caption\">Plugged in: the charger powers the Mac, and the battery is idle.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">When power comes from two places, or goes two ways, you see both: the battery helping a charger that can&#8217;t keep up, or the charger running the Mac and charging the battery at the same time.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1384\" height=\"575\" src=\"https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-flow-splits.png\" alt=\"Two Wattbar panels: on the left the charger and the battery both power the Mac; on the right the charger powers the Mac and charges the battery\" class=\"wp-image-708\" srcset=\"https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-flow-splits.png 1384w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-flow-splits-300x125.png 300w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-flow-splits-1024x425.png 1024w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-flow-splits-768x319.png 768w\" sizes=\"auto, (max-width: 1384px) 100vw, 1384px\" \/><figcaption class=\"wp-element-caption\">Left: the battery helps the charger. Right: charging while in use.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Prefer plain text? Set <em>Click shows<\/em> to <em>Simple menu<\/em> in Settings, or right-click Wattbar any time.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Made for the notch<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">On a MacBook with a notch, the right side of the menu bar fills up fast, and macOS quietly hides whatever doesn&#8217;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<h2 class=\"wp-block-heading\">Settings<\/h2>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"840\" height=\"1824\" src=\"https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-settings-1.1.png\" alt=\"The Wattbar Settings window with a live preview, readings, format and general settings\" class=\"wp-image-710\" style=\"width:420px;height:auto\" srcset=\"https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-settings-1.1.png 840w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-settings-1.1-138x300.png 138w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-settings-1.1-472x1024.png 472w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-settings-1.1-768x1668.png 768w, https:\/\/stigern.net\/blog\/wp-content\/uploads\/2026\/10\/wattbar-settings-1.1-707x1536.png 707w\" sizes=\"auto, (max-width: 840px) 100vw, 840px\" \/><figcaption class=\"wp-element-caption\">The Settings window. The preview at the top shows exactly how the menu bar will look.<\/figcaption><\/figure>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Choose per reading: icon and value, value only, icon only or hidden<\/li>\n\n\n\n<li>Stacked or single line layout<\/li>\n\n\n\n<li>Pick the Mac icon: laptop, bolt, gauge, chip or plug<\/li>\n\n\n\n<li>Decimals, the &#8220;W&#8221; unit, larger text and compact spacing<\/li>\n\n\n\n<li>Hide the battery reading when it&#8217;s idle<\/li>\n\n\n\n<li>Update every 1, 2 or 5 seconds, with optional smoothing<\/li>\n\n\n\n<li>Launch at login<\/li>\n<li>Click shows: the power flow panel or a simple menu<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Settings\u2026 is at the bottom of the panel and in the menu (\u2318,). If macOS has hidden the menu bar item anyway, open Wattbar from Spotlight and the Settings window comes up.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How it measures<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Wattbar reads the Mac&#8217;s System Management Controller directly, so it updates every second or two. The battery number is the battery&#8217;s own measured power, so when charging is paused, for example by a charge limit, Wattbar really shows 0.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">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&#8217;t available.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Getting started<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Unzip it and drag Wattbar to Applications. It&#8217;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.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>macOS 13 Ventura or later<\/li>\n\n\n\n<li>Apple silicon (M1 and newer)<\/li>\n\n\n\n<li>About 1 MB, no dependencies, nothing in the Dock<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">A note<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Like FuMachine, Wattbar was written with Claude. I made it for my own MacBook and it does what I wanted, and that&#8217;s the reason it&#8217;s here. No warranty and no support promise, but if it&#8217;s useful to you too, good.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Download<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong><a href=\"https:\/\/stigern.net\/software\/wattbar\/dl.php?f=Wattbar.zip\">Download Wattbar 1.1<\/a><\/strong> (zip, 0.7 MB)<\/p>\n\n\n\n<p id=\"wattbar-downloads\" class=\"has-small-font-size\" style=\"display:none\">Downloaded <strong>0<\/strong> times<\/p>\n<script>\nfetch('\/software\/wattbar\/counter.php', {cache: 'no-store'})\n  .then(r => r.ok ? r.json() : null)\n  .then(d => {\n    if (!d || typeof d.total !== 'number') return;\n    const p = document.getElementById('wattbar-downloads');\n    p.querySelector('strong').textContent = d.total.toLocaleString();\n    if (d.total === 1) p.lastChild.textContent = ' time';\n    p.style.display = '';\n  })\n  .catch(() => {});\n<\/script>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">SHA-256 22561b17ce80a19a086c863f22512f05841cc98b93b1639a94f84067141bac0f<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>New in 1.1:<\/strong> the animated power flow panel, and a choice between it and the simple menu.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Wattbar is free. If it\u2019s useful to you, you can <a href=\"https:\/\/buymeacoffee.com\/stigern4\">buy me a coffee<\/a> \u2615<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I wanted a small power meter in my Mac&#8217;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 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":709,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[374],"tags":[],"class_list":["post-695","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-software"],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":8}},"_links":{"self":[{"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/posts\/695","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/comments?post=695"}],"version-history":[{"count":10,"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/posts\/695\/revisions"}],"predecessor-version":[{"id":713,"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/posts\/695\/revisions\/713"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/media\/709"}],"wp:attachment":[{"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/media?parent=695"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/categories?post=695"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stigern.net\/blog\/wp-json\/wp\/v2\/tags?post=695"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}