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Uptime is a measure of system reliability, expressed as the percentage of time a machine, typically a computer, has been working and available. Uptime is the opposite of downtime.

Htop adds an exclamation mark when uptime is bigger than 100 days

It is often used as a measure of computer operating system reliability or stability, in that this time represents the time a computer can be left unattended without crashing, or needing to be rebooted for administrative or maintenance purposes.

Conversely, long uptime may indicate negligence, because some critical updates can require reboots on some platforms.[1]



In 2005, Novell reported a server with a 6-year uptime.[2][3] Although that might sound unusual, that is actually common when servers are maintained under an industrial context and host critical applications such as banking systems.

Netcraft maintains the uptime records for many thousands of web hosting computers.

A server running Novell NetWare has been reported to have been shut down after 16 years of uptime due to a failing hard disk.[4][5]

Determining system uptimeEdit

Microsoft WindowsEdit

Using systeminfoEdit

Users of Windows XP Professional, Windows Server 2003 and Windows Vista systems can type systeminfo at the Command Prompt to display all system information, including the System Up Time.[6]

C:\>systeminfo | findstr "Time:"
System Up Time:            0 Days, 8 Hours, 7 Minutes, 19 Seconds

Note: Windows Vista Business 64-bit and Windows 7 do not return a "System Up Time" but "System Boot Time" instead. Also note that the exact text and date format is dependent of the language and locale Windows is running.

Note: Windows 7's "System Boot Time" is not a reliable indicator of boot time. It does not take into account the time spent in sleep or hibernation mode. Hence, the boot time drifts forward every time the computer is left in sleep or hibernate mode.

Using net statistics server/workstationEdit

C:\>net statistics workstation | findstr "since"
Server Statistics for \\COMPUTERNAME

Statistics since 8/31/2009 8:52:29 PM

The line that start with "Statistics since ..." provides the time that the server was up from. The command "net stats srv" is shorthand for "net statistics server."[7] The exact text and date format is dependent of the language and locale Windows is running.

Using Uptime.exeEdit

Microsoft has also provided a downloadable utility:[8]

SYSTEMNAME has been up for: 2 day(s), 4 hour(s), 24 minute(s), 47 second(s)

Note: The Windows 7 Uptime.exe utility is not a reliable indicator of total uptime. It gives the same wrong information and boot time as the Task Manager Uptime. It does not take into account the time spent in sleep or hibernation mode.[citation needed] An alternative to the Uptime.exe utility is "net statistics workstation" under "Statistics".

Using Windows Management Instrumentation (WMI)Edit

Uptime can also be determined via WMI from the command-line with wmic:

C:\>wmic os get lastbootuptime

The timestamp is in the format yyyymmddhhmmss.nnn, so this is a computer that last booted up on 8 May 2011 at 16:17:51.822. WMI can also be used to find the boot time of remote computers as well (Windows permissions allowing), for example with WMIC:

C:\>wmic /node:"my-server" os get lastbootuptime

The text "LastBootUpTime" and the timestamp format are always the same regardless of the language and locale, Windows is running.

WMI can also be used via a programming language such as VBScript or Powershell[9][10]

Using Windows Task ManagerEdit

Users of Windows Vista, Windows 7 and Windows 8 can see uptime in Windows Task Manager under the tab Performance. The uptime format is DD:HH:MM:SS


The uptime command is also available for FreeDOS. The version was developed by M. Aitchison.[11]


Using uptimeEdit

Users of Linux systems can use the BSD uptime utility, which also displays the system load averages for the past 1, 5 and 15 minute intervals:

$ uptime
  18:17:07 up 68 days,  3:57,  6 users,  load average: 0.16, 0.07, 0.06

Using /proc/uptimeEdit

Shows how long the system has been on since it was last restarted:

$ cat /proc/uptime
  350735.47 234388.90

The first number is the total number of seconds the system has been up. The second number is how much of that time the machine has spent idle, in seconds.[12] On multi core systems (and some linux versions) the second number is the sum of the idle time accumulated by each CPU.[13]


Using uptimeEdit

BSD-based operating systems such as FreeBSD, Mac OS X and SySVr4 have the uptime command (See uptime(1) – FreeBSD General Commands Manual).

$ uptime
3:01AM  up 69 days,  7:53, 0 users, load averages: 0.08, 0.07, 0.05

Using sysctlEdit

There is also a method of using sysctl to call the system's last boot time:[14]

$ sysctl kern.boottime
kern.boottime: { sec = 1271934886, usec = 667779 } Thu Apr 22 12:14:46 2010


Users of OpenVMS systems can type show system at the DCL command prompt; the header (first) line of the resulting display includes the system's uptime.[15]

$ show system/noprocess
OpenVMS V7.3-2 on node JACK 29-JAN-2008 16:32:04.67  Uptime  894 22:28:52

The uptime is displayed following the Uptime label as days followed by hours:minutes:seconds. In this example, the command qualifier /noprocess simply suppresses the display of per-process detail lines of information.

See alsoEdit


  1. ^ "How to install multiple Windows updates or hotfixes with only one reboot". Retrieved 2014-04-22.
  2. ^ "Marathon servers". 2005-12-01. Retrieved 2014-04-22.
  3. ^ "Cool Solutions: Uptime Workhorses: Still Crazy after all these Years". Retrieved 2014-04-22.
  4. ^ Bright, Peter (2013-03-29). "Epic uptime achievement unlocked. Can you beat 16 years?". Ars Technica. Retrieved 2014-04-22.
  5. ^ "So long to a valiant companion - Ars Technica OpenForum". Retrieved 2014-04-22.
  6. ^ "Tracking down uptime in Windows XP | TechRepublic". Archived from the original on 2012-07-08. Retrieved 2014-04-22.
  7. ^ Yuval Sinay (2006-10-25). "How to find Windows uptime?". Retrieved 2014-04-22.
  8. ^ "Uptime.exe Tool Allows You to Estimate Server Availability with Windows NT 4.0 SP4 or Higher". 2012-08-20. Archived from the original on 2014-04-24. Retrieved 2014-04-22.
  9. ^ "How Can I Tell if a Server has Rebooted? - Hey, Scripting Guy! Blog - Site Home - TechNet Blogs". Retrieved 2014-04-22.
  10. ^ "How Can I Determine the Uptime for a Server? - Hey, Scripting Guy! Blog - Site Home - TechNet Blogs". Retrieved 2014-04-22.
  11. ^
  12. ^ "Red Hat Enterprise Linux 6: Deployment Guide". Retrieved 2018-12-12.
  13. ^ "Martin Schwidefsky: Re: [PATCH] Re: /proc/uptime idle counter remains at 0". LKML. Retrieved 2014-04-22.
  14. ^ "Mac Developer Library". Retrieved 2014-04-22.
  15. ^ "OpenVMS Undocumented Features". 2008-10-29. Retrieved 2014-04-22.