On my OS X Mavericks my time is always a few minutes (about 4 minutes) ahead of my iOS 7.1.2 iPhone. Both devices are set to set the date and time automatically.

On my Mac I can choose from:

  • Apple Americas/U.S. (time.apple.com.)
  • Apple Asia (time.asia.apple.com.)
  • Apple Europe (time.euro.apple.com.)

but these do not differ more than a second or so.

On my iPhone I can only choose 'Set Automatically'.

Why is there a difference between both times? And which one is 'real'?

Screenshot taken with a few seconds in between (believe me ;) osx time settings iphone time settings

  • Does my iPhone use a non-apple time server? Commented Jul 10, 2014 at 8:34
  • Can I resize my iPhone screenshot using this forums engine? (might be a valid discussion..) Commented Jul 10, 2014 at 8:37
  • As regards which one is real, I like the website at time.gov - I can work out timezone differences myself from that easily enough Commented Jul 10, 2014 at 9:50
  • @MarkSetchell, well the iPhone is right according to your clock. (btw, that site sucks horribly in obeying WWW etiquette) Commented Jul 10, 2014 at 10:51
  • Is it possible that Parallels is responsible for this? Commented Jul 10, 2014 at 15:47

2 Answers 2


The iPhone does not use NTP to synchronize its clock. It uses a feature of the cellular network. I can't tell you why your Mac's clock is off that far, but I suggest you use nl.pool.ntp.org instead of time.euro.apple.com.

  • Funny, using nl.pool.ntp.org will not change my time at all. This might be because my 'correction factor' is wrong. I have had issues with this because of Parallels... Commented Jul 10, 2014 at 15:45
  • 1
    Similar, but this worked: apple.stackexchange.com/a/119485/55028 Commented Jul 30, 2014 at 19:12

It's possible your ntp.drift file is something insane - check /var/db/ntp.drift, delete it if necessary, and restart (kill) ntpd.

  • I have no /var/db/ntp.drift on my OS X Mavericks. Strange, because I do have a /usr/sbin/ntpd -c /private/etc/ntp-restrict.conf -n -g -p /var/run/ntpd.pid -f /var/db/ntp.drift process running... And rebooting does not solve my issue, so I think killing ntpd doesn't either. Commented Jul 10, 2014 at 15:42
  • 1
    What qualifies as an insane value in this file? Commented Oct 19, 2018 at 19:02

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