How to Check Mac Uptime

Open Terminalfrom Applications > Utilities or by searching in Spotlight, then type uptime and press Return. The output includes the current time, how long the system has been running, the number of logged-in users, and three load averages.

For an alternative view, use sysctl kern.boottime. This command shows the exact date and time of the last boot, which is useful when you need to know precisely when the Mac was last restarted rather than just how long it has been running.

Click the Apple menu in the top-left corner of your screen, select About This Mac, click More Info, then open System Report. In the left sidebar, click Softwareto see the "Time since boot" field.

This shows the same information as the Terminal uptime command but in a graphical interface. It is a good option if you prefer not to use the command line.

Load averages indicate how busy your system has been over the past 1, 5, and 15 minutes. Each number represents the average count of processes that were either actively using the CPU or waiting for CPU time during that interval.

On a Mac with 8 cores, a load average of 8.0 means all cores are fully utilized. Load averages above the core count indicate the system is overloaded and processes are queuing up to wait for CPU time.

Lower load averages are better for responsiveness. If the 1-minute average is significantly higher than the 15-minute average, it means a recent spike in activity. If all three numbers are consistently high, the system is under sustained heavy load.

Applications that do not properly release memory cause leaks that accumulate over time. The longer the system runs without a restart, the more memory is consumed by processes that no longer need it.

Kernel caches grow over time as the system accumulates temporary data. Login agents and background services may hang silently, consuming CPU and memory without providing any useful work. Restarting clears all of this and returns the system to a clean state.

If your Mac feels slow, check uptime first. A simple restart often resolves performance issues caused by accumulated system state. Restarting once a week is a good practice for keeping macOS responsive and stable.

MoniThorformats uptime as days, hours, and minutes. For example, a system running for over a day shows "14d 3h 27m" while a system running for less than a day shows "3h 15m". This is always visible without opening Terminal or System Information.

Load averages (1-minute, 5-minute, 15-minute) are also shown in the CPU section alongside overall CPU usage and per-core bars. This gives you a complete picture of system load and how long the system has been running in one place.

Visit the Features page for a complete list of monitored metrics, or return to the home page for an overview of MoniThor.

To reset uptime, click the Apple menu and select Restart. Alternatively, shut down the Mac completely and power it back on. Both methods reset the uptime counter to zero.

Sleep does not reset uptime. When a Mac sleeps, the system stays loaded in memory and the kernel continues tracking time since boot. Closing the lid or letting the Mac go idle does not count as a restart.

If you use your Mac primarily in clamshell mode with an external display, remember to restart periodically. Clamshell mode keeps the system running continuously, and it is easy to go weeks or even months without a restart.