The best system monitor apps for Mac
By Vishva Variya · Updated
Short answer
Activity Monitor is free and shows every process. For live readings in the menu bar, Stats is free and open source, and iStat Menus ($11.99) is the most detailed, with fan control and S.M.A.R.T. status. TG Pro ($10) specialises in temperatures and fans, DriveDx in drive failure warnings, and Sensei adds cleanup to monitoring. Peekaboo’s Mac Health gives a 0–100 score with the reason for every lost point and the tools to fix a full disk.
How we picked. Prices, macOS requirements and features from each vendor’s own site, GitHub page or App Store listing, checked November 3, 2026. “System monitor” covers several jobs (live readings, temperatures and fans, drive health, an overall verdict), so each app is listed for the one it does best. Peekaboo is our app; it’s listed with its gaps, like the others.
Before you buy anything: Activity Monitor (built in)
Free, in Applications › Utilities. It lists every process with its CPU, memory, energy, disk and network use, shows memory pressure, and can force quit. It has no menu bar readings beyond a Dock icon graph, no temperatures, no drive health and no overall verdict.
At a glance
| App | Best for | Price | Requires |
|---|---|---|---|
| iStat Menus | Best for: The most detailed menu bar monitor, with fan control | Price: $11.99 Single, $14.99 Family; also in Setapp | Requires: macOS 13.5 or later |
| Stats | Best for: A free, open-source menu bar monitor | Price: Free (MIT licence) | Requires: macOS 12 or later |
| Peekaboo | Best for: A health score with reasons, and the fix for a full disk | Price: $24.99 one-time (launch price $9.99 until Nov 13) | Requires: macOS 14 Sonoma |
| TG Pro | Best for: Temperatures and fan control, $10 once | Price: $10 one-time | Requires: macOS 10.14 or later |
| DriveDx | Best for: Warning you before a drive fails | Price: $24.99 Personal (up to 3 Macs), $49.99 Family | Requires: macOS 10.9 or later |
| Sensei | Best for: Monitoring and cleanup in one app | Price: $29/year, or $59 one-time (up to 3 Macs) | Requires: macOS 14 or later |
Stats: A free, open-source menu bar monitor
Free, open-source menu bar monitor: CPU, GPU, memory, disk, network, battery and sensors.
- Free and open source (MIT)
- Menu bar modules for CPU, GPU, memory, disk, network, battery, sensors
- Bluetooth device battery levels
- Installs with Homebrew
Gaps: Its fan control is in legacy mode and no longer maintained, and like most monitors it has no cleanup tools.
Free (MIT licence) · macOS 12 or later · source: github.com/exelban/stats (README, LICENSE, releases), verified 2026-11-03
Peekaboo: A health score with reasons, and the fix for a full disk
Mac Health (⌥⇧⌘H) shows processor, memory, startup disk, network, heat and battery, the apps keeping your Mac busy or awake, and a 0–100 score with a sentence and a fix for every lost point. A week of readings stays on your Mac.
- 0–100 score in fixed bands, with the reason for each lost point
- A week of history, one reading every five minutes
- Optional menu bar readings for processor, memory pressure and network
- Clean Up, Duplicates and Space Map for when the disk is the problem
Gaps: No per-sensor temperatures, fan control, GPU graphs or S.M.A.R.T. drive health.
$24.99 one-time (launch price $9.99 until Nov 13) · macOS 14 Sonoma
TG Pro: Temperatures and fan control, $10 once
Temperatures for every sensor plus fan control with Auto Boost rules, $10 once.
- Temperature readings for CPU, GPU, drives and more
- Manual fan control and Auto Boost rules
- Temperature notifications
- Runs on macOS 10.14 to 27, Intel and Apple silicon
Gaps: It’s built around temperatures and fans; memory, network and disk cleanup aren’t on its feature list.
$10 one-time · macOS 10.14 or later · source: tunabellysoftware.com/tgpro and its release notes, verified 2026-11-03
DriveDx: Warning you before a drive fails
Drive health specialist: SSD and HDD failure indicators, self-tests and email reports.
- Failure indicators for SSDs and HDDs
- Drive self-tests
- Warnings and email reports
- Runs on macOS 10.9 to 27
Gaps: It looks after drives only: processor, memory and network, and freeing space, are outside its scope.
$24.99 Personal (up to 3 Macs), $49.99 Family · macOS 10.9 or later · source: binaryfruit.com/drivedx and binaryfruit.com/store, verified 2026-11-03
Sensei: Monitoring and cleanup in one app
Cleaner and monitor in one: uninstaller, junk and cache cleanup, live CPU, GPU, battery and storage, disk benchmark.
- Uninstaller that removes leftovers
- System junk, old caches and large files
- Live CPU, GPU, battery health and storage
- Disk benchmark and SSD Trim
Gaps: The one-time licence covers versions 1 and 2 only, and a duplicate finder or a visual disk map isn’t on its feature list.
$29/year, or $59 one-time (up to 3 Macs) · macOS 14 or later · source: cindori.com/sensei, cindori.com/store/sensei and Cindori’s support pages, verified 2026-11-03
Questions
How do I check my Mac’s health?
- Open Activity Monitor for processes and memory pressure, System Settings › General › Storage for disk space, and System Settings › Battery for battery condition. A monitor app puts those in one place; Peekaboo’s Mac Health also scores them and says what to fix.
What is the best free system monitor for Mac?
- Stats: it’s open source under the MIT licence, shows CPU, GPU, memory, disk, network, battery and sensors in the menu bar, and installs with Homebrew. It needs macOS 12 or later.
Which Mac monitor can control fan speed?
- iStat Menus and TG Pro both offer fan control. Stats lists its fan control as unmaintained legacy mode.
Can a monitor tell me if my SSD is failing?
- DriveDx focuses on exactly that, and iStat Menus shows S.M.A.R.T. status. Keep a backup either way: drives can fail without warning.