Find Uptime on Mac: How to Check

To find out how long your Mac has been running since its last restart, open the Terminal app and run the command uptime. The output shows the current time, how long the system has been up, how many users are logged in, and the system load averages; alternatively, you can see the same information in the System Information app under the Software section.

Why Uptime Matters

Uptime is the amount of time a computer has been continuously powered on and running without a shutdown, restart, or sleep-wake cycle that resets the kernel. For Mac users, knowing the uptime helps in several practical situations:

• Troubleshooting: If you are experiencing slow performance or memory issues, a very long uptime can indicate that a restart might clear temporary files and reset system processes.
• Verifying restarts: After installing macOS updates or system extensions, you can confirm that the system actually rebooted as part of the process.
• Monitoring servers or always-on Macs: If you use a Mac as a home server or media center, uptime tells you if it has crashed and rebooted unexpectedly.
• Scheduling maintenance: Knowing when the last restart occurred helps you plan reboots for updates or performance reasons.

How to Check Uptime with the Terminal

The most direct and reliable method is using the built-in uptime command. Here is how:

1. Open Terminal (found in /Applications/Utilities/ or via Spotlight by pressing Command+Space and typing “Terminal”).
2. Type uptime and press Return.
3. Read the output. For example: 14:23 up 3 days, 4:12, 2 users, load averages: 1.02 1.05 1.01

The first part (up 3 days, 4:12) is the uptime. The load averages (three numbers) represent the average number of processes waiting to run over the last 1, 5, and 15 minutes; they are not directly related to uptime but are useful for diagnosing system load.

Checking Uptime in System Information

If you prefer a graphical interface, macOS includes a System Information app that displays uptime:

1. Hold the Option key and click the Apple menu (), then choose System Information (or open it from /Applications/Utilities/).
2. Select Software in the left sidebar.
3. Look for the Time since boot entry. It shows the exact date and time the Mac was last started, so you can calculate the uptime yourself.

Note: On newer macOS versions (Ventura and later), the System Information app is still available, but some users may find it under “More Info” in System Settings. The path is essentially the same.

What About Activity Monitor?

Activity Monitor does not directly show total uptime, but it can give you a clue. If you look at the Memory tab, the “Used Memory” and “Cached Files” values can be high after long uptimes, but that is not a reliable indicator. The Disk tab shows “Time Since Boot” for each process, but that is per-process, not system-wide. So while Activity Monitor is useful for other diagnostics, it is not the best tool for this specific question.

Common Misconceptions About Uptime

One frequent misunderstanding is that sleep mode resets the uptime. It does not. When your Mac goes to sleep, the system is still running, and the uptime clock keeps counting. Only a full shutdown, restart, or forced reboot resets the uptime. Similarly, closing the lid on a MacBook does not reset uptime; it just sleeps.

Another misconception is that a high uptime is inherently bad. While it is true that some system processes (like the WindowServer or kernel extensions) may develop memory leaks over time, macOS is generally stable enough to run for months without a restart. If you do not experience problems, a long uptime is not a cause for concern.

How to Reset Uptime

If you want to reset the uptime (for testing or to clear a potential issue), simply restart your Mac. You can do this from the Apple menu () > Restart. A shutdown also resets uptime, but a restart is faster and does not require you to reopen all your apps manually (though macOS will reopen them automatically if you have “Reopen windows when logging back in” selected). There is no command to artificially zero the uptime without a reboot.

Using Uptime for Diagnostics

When you contact Apple Support or a technician, they may ask for your uptime to determine if a problem is related to a long-running system. For example, if your Wi-Fi drops every few hours, they might ask you to check uptime to see if the system has been up for days. In that case, a restart is often the first recommended step. Additionally, if you are troubleshooting a kernel panic, the system will automatically restart, so the uptime will be short (e.g., “up 2 minutes”) right after the crash. That is a useful diagnostic sign.

Frequently Asked Questions

Does the uptime command work on all Macs?

Yes, the uptime command is part of the standard Unix layer in macOS and works on every Mac model, from Intel to Apple Silicon (M1, M2, M3). The output format is identical across versions.

Can I see uptime without using Terminal?

Yes, the System Information app shows “Time since boot” under the Software section. You can also use third-party menu bar apps, but they essentially read the same system data.

Why does my Mac show a very long uptime even after I shut it down?

If you shut down your Mac but then turn it on again, the uptime resets. However, if you use the “Restart” option, it also resets. The only way uptime persists is if you never actually shut down or restart. If you see a long uptime after a shutdown, it is possible that the shutdown was not completed (e.g., a hung app prevented the shutdown, and the system rebooted instead). Check the “Time since boot” in System Information to see the exact boot time.

Is there a way to see uptime in the menu bar?

Not natively, but you can use third-party apps like iStat Menus or Stats, which display uptime in the menu bar. These apps read the same system data and are safe to use, but they are not necessary for casual checking.

Does uptime affect performance?

In general, no. macOS is designed to run for long periods without degradation. However, if you have third-party kernel extensions (kexts) or apps with memory leaks, you might notice slowdowns after weeks of uptime. A simple restart clears those issues.

Can I find out when my Mac was last rebooted without Terminal?

Yes, the System Information app shows the exact boot time. You can also check the “Last Boot” field in the “Hardware” section of System Information, but that is not present in all versions. The most reliable method is the Terminal command sysctl -n kern.boottime, which prints the boot time as a Unix timestamp.

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