Watt's LeftA free Windows app that shows how much power is flowing into your battery from the charger and how much your laptop is drawing out, live. Plus real time left, stored energy, voltage and health.
Get it free on the Microsoft StoreWindows 11 and Windows 10 · x64 and ARM64 · no account, no tracking
Power flowing into the battery right now. Higher means faster charging. It slows on purpose near full to protect the battery.
Power the laptop is using from the battery. A bright screen, video calls and heavy work push it up. Lower means it lasts longer.
Energy left divided by your average draw over the last five minutes, refreshed every thirty seconds, so it doesn't twitch.
The actual fuel in the tank, in watt-hours, against what a full charge holds today. Percent is only the gauge needle.
The battery's electrical pressure, which creeps up as it fills and sags under load.
How much a full charge holds now compared with when the battery was new, and how many full charges it has been through.
Hover any number for a one-sentence explanation in plain words. Thirty-minute graphs of charge, watts and voltage are one toggle away and survive a restart. The tray icon shows the percent. And there's a party mode, which you'll find.
Percent tells you how full the tank is. Watts tell you how fast you're emptying it, and that is the number you can actually change. Close a tab, dim the screen, and you see the draw drop within a second. Plug into a weak charger and you see it charging at 15 W instead of 65 W, which is why it will take all afternoon.
Windows shows percent and an estimate of time remaining, but no power figure. The battery hardware reports its charge and discharge rate all the same. Watt's Left reads that through the standard Windows battery interface, the same one tools like HWiNFO use, four times a second, and shows only that.
The honest limit: Windows only exposes what reaches the battery, never the charger's total output. When you're plugged in, OUT shows a dash rather than a made-up number, because no software on Windows can measure what comes through the cable.
| App | Live watts in / out | Price | Feel |
|---|---|---|---|
| Watt's Left | Yes, front and centre | Free | One window, big numbers, plain-English hover cards, graphs |
| HWiNFO | Yes, buried in a sensor list | Free | Hundreds of sensors for every part of the machine |
| BatteryInfoView (NirSoft) | Yes, as a table row | Free | A twenty-field table, unchanged since 2012 |
| Battery Flyout | Yes, in graphs | Paid | Replaces the Windows battery flyout; adds Bluetooth device batteries |
| Pure Battery Analytics | Rates in the analytics | Free | Charts, alarms, live tiles |
| Windows itself | No | — | Percent and an estimate only |
If you want every sensor in the machine, HWiNFO is excellent. If you want to know what your battery is doing, at a glance, this is the one.
Install Watt's Left. The OUT number is the watts your laptop is drawing from its battery right now, updated four times a second. It only reads while you're on battery, because when plugged in the laptop runs off the charger.
No. Windows shows the percent and an estimated time remaining, but no power figure. The battery hardware reports its charge and discharge rate, and Watt's Left reads it through the standard Windows battery interface.
No. Windows exposes only what reaches the battery, never the charger's total output. While charging, Watt's Left shows the watts going into the battery, which is the charger's output minus what the laptop is using at that moment.
Free, no account, no ads, no in-app purchases, no tracking. It's a small app by one person who wanted this number and couldn't find it anywhere clean.
No. It makes no network connections at all. Your settings and a half hour of readings live in the app's private folder on your own computer and are removed on uninstall. Privacy policy.
It's the energy left divided by your average draw over the last five minutes, refreshed every thirty seconds. Steadier than the instantaneous figure Windows uses. Heavier work will still drain faster than any estimate.
Windows 11, and Windows 10 from build 19041, on x64 and ARM64 laptops. It needs a battery; on a desktop it reports that none was found.