Tray applet that measures how many units (kWh) of electricity your laptop pulls from the wall: the thing your bill actually charges you for.
- Samples power once a second and integrates it into energy
- Tracks today / this month / lifetime, in units and in money
- Live wattage drawn into the tray icon
- Plain-CSV ledger you can open in a spreadsheet and check
Nothing on a laptop measures wall draw directly, so it uses two sources:
| Source | Accuracy | |
|---|---|---|
| On battery | The pack's fuel gauge, over IOCTL_BATTERY_* |
Measured. The best sensor on the machine. |
| On AC | CPU package + GPU + a learned baseline, then adapter losses | Modelled. |
The baseline (panel, board, RAM, SSD, fans) is learned while you are on
battery, bucketed by screen brightness, and replayed on AC. Every reading is
labelled MEASURED, MODELLED or ESTIMATED so you know which you are looking
at.
- Download
JuiceMeter-win-x64-self-contained.zipfrom the latest release - Unzip anywhere
- Right-click
JuiceMeter.exe→ Run as administrator
No installer, no service, nothing to uninstall. Delete the folder and it is gone.
The exe is not code-signed, so the first launch shows "Windows protected your PC". Click More info, then Run anyway. You will then get the usual UAC prompt.
Admin is what unlocks CPU package power. Without it the app still runs and battery measurement is exact, but AC figures stay rough estimates and the baseline never learns. Tick Run on startup inside the app and it registers a scheduled task, so it comes back elevated at login with no UAC prompt.
The self-contained zip is ~60 MB because it carries the .NET runtime.
JuiceMeter-win-x64.zipis the same app at ~1 MB, but needs the .NET 8 Desktop Runtime already installed.
- Windows 10 or 11, x64
- A laptop with a smart battery (any modern one)
Discrete GPU power needs NVIDIA (NVML). Switching between Standard and Eco in G-Helper is safe.
Closing the window parks it in the tray; quit from the tray menu. The tray icon shows live watts, with a coloured bar for the source (amber = battery, teal = charging, blue = AC). Right-click it for today's and this month's units.
| Flag | Effect |
|---|---|
--tray |
Start hidden in the tray. |
--probe [seconds] |
Dump every sensor and how the model turns it into watts, then exit. |
--screenshot [file] |
Render the dashboard to a PNG. --settings, --light, --dark also accepted. |
%LOCALAPPDATA%\JuiceMeter\ holds one CSV per month, one row per minute, plus
state.json for lifetime totals.
Sleep and hibernate are recorded as gaps, not integrated across. "Reset counters" never deletes anything; it moves the history folder aside.
Adapter (90%) and charging (92%) efficiency are assumptions, not measurements. Change them in Settings if you own a wall meter. Anything the package sensors cannot see (USB charging, an external drive) lands outside the model. A wall socket meter is still ground truth; this is the closest you get from inside the machine.
.NET 8 + WinForms · LibreHardwareMonitor
for CPU/GPU · Win32 DeviceIoControl for the battery
Building it yourself needs the .NET 8 SDK: clone, then .\build.ps1
(-SelfContained to bundle the runtime). Output lands in dist\.
MIT. See LICENSE.