Check a Macs Uptime and Reboot History
Macs are very stable and generally OS X users rarely have to reboot their machines. Not to brag or anything, but I love the fact that that unless I have run Software Update, I rarely have to reboot my Mac at all, and while this might not be that exciting to most Mac users, for a relatively recent Windows convert I find this particularly nice. So naturally with my Mac geekiness I find it fun to check the uptime and reboot history of my Mac and others, it’s easy to do and it’s actually functionally useful too for troubleshooting certain Mac problems. Here’s how to do both via the Command Line.
How to Check a Macs uptime
To check your Macs uptime, simply type ‘uptime’ in the Terminal. Terminal is an application found within /Applications/Utilities/ and is included in every version of Mac OS X. In the below example, uptime is reporting that we have a Mac that has been up for 21 hours and 40 minutes.
YourMac:~ user$ uptime
10:33 up 21:40, 4 users, load averages: 0.09 0.19 0.21
uptime will vary per machine, depending on how frequently it is rebooted. Speaking of restarting a machine, you can also retrieve reboot history through the command line as well.
How to Check a Macs reboot history
To check the reboot history of your Mac, type ‘last reboot’ in the Terminal. This will provide you with the dates and times of the last few reboots the machine has gone through.
YourMac:~user$ last reboot
reboot ~ Tue Sep 22 12:52
reboot ~ Sun Aug 30 23:17
reboot ~ Sat Aug 29 01:12
reboot ~ Fri Aug 28 22:07
wtmp begins Fri Aug 28 22:07
This can be extremely helpful when troubleshooting, or even just for finding out how often a Mac gets booted, and is a nice command to use in addition to uptime.
Find “Time Since Boot” from System Information
Outside of the command line, you can also retrieve uptime information from the more familiar GUI:
- Pull down the Apple menu and hold down the OPTION key, then select “System Information”
- Click on “Software” on the side menu to see “System Software Overview”
- Look for “Time since boot” to see the uptime in days, hours, and minutes
This method is easier though it own’t provide you with user information, load averages, or the reboot history.
Updated on 4/12/2013
“last reboot” doesn’t work for me for some reason (OS 10.5.8). I had to do “last | grep reboot”
[...] any updates or new apps recently, and my Mac hasn’t been rebooted in 9 days (you can check your Mac’s uptime with the terminal). It’s a bit of a mystery to me as to what caused it, but the above fix [...]
[...] you’re looking for a record of a Macs boot history, try using the “last reboot” command instead. Similarly if you’re only looking to [...]
Great and usefill knowledge! thank you Bill.
Thanks, quite useful!
Is there a non-Terminal/GUI way to check uptime?
For example, in Windows you can see it in the Task Manager.
Yes, you can retrieve the uptime from the System Information menu. We updated the article with instructions on how to do this on all versions of Mac OS X.
Thanks for the comment!