Total system power (W)
When your Mac exposes battery sensor data, PowerWatt shows total system power in watts.
- OUT W: power leaving the battery (discharging)
- IN W: power going into the battery (charging)
- Net: IN − OUT, for one-number monitoring
Free · Menu bar utility · macOS 15.2+
Know your Mac’s real power draw.
PowerWatt shows real-time battery power usage—IN or OUT watts—without clutter. Pick the display style that fits your workflow and leave it running in the menu bar.
- Instant net watts or separate IN/OUT readings
- Per-app energy tracking with Activity Monitor-style attribution
- Smoothing + refresh controls to tame noisy spikes
- Sortable “Top Consumers” table with in-app unit explanations
- Automatically falls back to Relative mode when total watts aren’t available
- Telemetry is optional and off unless you opt in
Free to download. Runs in the menu bar only. No Dock icon, no distractions.
What PowerWatt measures
PowerWatt combines battery sensors (when available) with Activity Monitor-style attribution to help you understand both overall power draw and which apps are driving it.
Energy over time (Wh / mWh)
Energy is power accumulated over time, shown per app and for the selected range.
- Energy helps compare apps across longer sessions
- 1 Wh = 1000 mWh
Per-app attribution (Watts or Relative)
PowerWatt estimates per-app impact from CPU time, disk I/O, and wakeups.
- Watts mode: allocates total system power across apps (when available)
- Relative mode: unitless “energy impact” score when total watts can’t be read
Total system watts are often unavailable while plugged in/charging. When that happens, PowerWatt automatically
prefers Relative mode so your charts and rankings remain meaningful.
Core features
PowerWatt keeps the interface calm while still surfacing the controls you need most often.
Real-time battery watts
Shows IN/OUT watts from battery sensors when available (and explains when total watts can’t be read).
Per-app energy tracking
See which apps consume the most energy with Activity Monitor-style attribution and 24-hour history.
Two display modes
Pick a net view (IN−OUT) or separate IN and OUT labels for detailed profiling.
Usage charts and insights
Total power over time, stacked per-app energy charts, and a top consumers table with sortable columns and in-app unit explanations.
Watts or Relative (auto)
When total system watts are unavailable (often while charging), PowerWatt automatically uses Relative mode so rankings and charts still work.
Smoothing controls
Adjust refresh rate (1–60 s) and smoothing windows (0–30 s) to reduce flicker.
Menu bar styles
Choose icon + watts, watts only, or prefix + watts—optionally color-coded for direction.
Start at login
Keep PowerWatt pinned in your menu bar and let Sparkle manage future updates.
Privacy-first
No telemetry is sent unless you explicitly opt in. All usage data stays on your Mac.
Free & open source
PowerWatt is free to download and open source. If it helps, you can support development with a coffee.
Install in two steps
- Download the
PowerWatt.dmg. - Install into
/Applications, launch the app, and open preferences from the menu bar.
If macOS blocks the first launch, right-click
PowerWatt.app and choose Open.
Leave it in /Applications for smooth updates and automatic “Open at Login” behavior.
Privacy-first by design
Anonymous usage stats stay off by default. When you first launch PowerWatt you can opt in (or not), and the toggle remains available later in Preferences.
Read the full privacy note for the exact data sent when telemetry is enabled.
Change log
Stay in the loop as we ship refinements to the menu bar experience.
PowerWatt v1.1.2
Highlights in this release:
- Sortable “Top Consumers” table with in-app unit explanations
- Automatically falls back to Relative mode when total watts aren’t available (common while charging)
- Improved website copy and screenshots
Need an older version? Browse the full release history on GitHub.
Quick answers
How does PowerWatt calculate watts?
Battery voltage (mV) × current (mA) ÷ 1,000,000 gives watts. PowerWatt reads those values directly from macOS.
Why are total watts sometimes unavailable while charging?
On some Macs, macOS does not expose reliable total power while plugged in/charging for long stretches. In those cases PowerWatt shows Relative metrics instead, so you still get useful rankings and charts.
Why do values sometimes jump?
Short spikes are normal as macOS shifts CPU/GPU load. Lower the refresh interval or enable smoothing to average them out.
How is per-app power estimated?
PowerWatt uses Activity Monitor-style attribution based on CPU time, disk I/O, and system wakeups. The total system power is proportionally allocated to apps based on their relative activity.
Does it work on desktops?
PowerWatt relies on battery stats for total watts, so it’s intended for Macs with a battery. The per-app tracking works on any Mac but may show relative scores instead of estimated watts.
Where is usage data stored?
All usage data is stored locally in SQLite under ~/Library/Application Support/PowerWatt. No per-app data is ever transmitted.
Where do I report issues?
Open an issue on GitHub with your macOS version and what you expected to see.