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Why is my PC's clock wrong?


Why is Internet time four or five minutes ahead of Network TV time?
I set my VCR according to my computer and recordings are late to start
and last too long. Had to put it back the way it was.

My experience is actually the opposite of yours – a couple of
networks seem to “run late” and I end up missing the crucial last
minute or two of shows from time to time.

So I can’t speak for the TV networks, other than to suspect that
some simply don’t do time very well, perhaps intentionally or

But we can look at your computer and this concept of “internet

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Let’s be clear, there is no such thing as “internet time”. There is
time – official and calibrated time – in the form of a clock made
available over the internet, but there’s no special time or time source
specifically for the internet.

The official time for the United States is maintained by the U.S.
Naval Observatory. At you’ll find all sorts of
information about how the USNO maintains the current time to an
accuracy of something like 10 nanoseconds or 10 billionth’s of a

“… there is no such thing as ‘internet

The USNO makes the current time available via several mechanisms (on
their web site, for example), but the one we’ll care about for our
purposes today is made available on the internet via a protocol called
“NTP” or Network Time Protocol. Via a network of servers to distribute
the load, any computer on the internet can ask “what time is it?” and
get a highly accurate response.

And Windows is ready to ask that question every so often to make
sure your clock is accurate, and stays accurate.

In Windows XP and Vista right click on the clock in your task bar
and click on Adjust Date/Time.

Date and Time properties in Windows XP

Ignore the time for now. Instead, click on the Time
tab (or in Windows Vista, click on the Change
time zone…
button to get a somewhat similar dialog):

Date and Time Timezone properties in Windows XP

Make sure that your time zone is set correctly, selecting from the
dropdown list. Also make sure that Automatically adjust clock
for daylight saving changes
is checked.

Now click on the Internet Time tab:

Date and Time Internet Time properties in Windows XP

Make sure that Automatically synchronize with an Internet
time server
is checked. The default time server is typically which should be sufficient. The dropdown list will
also include alternatives, typically in the United
States, which is also a fine alternative. (In Windows Vista you’ll have
to click a Change settings button to make changes.)
You can also select another time server by typing its name in as

As you can see, the dialog lets you know when the last time update
was performed, and when the next one will be. Alternately, you can
always click on the Update Now button to force an
immediate update.

Once you’ve done so, your clock should be as accurate as it can
be. If the TV networks are off, well that’s their problem not yours I’m
afraid, and out of your control.

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13 comments on “Why is my PC's clock wrong?”

  1. how do one contact Microsoft when a country has extended the daylight saving time and Microsoft has not updated the change?

    MS dont really have a bug/issue reporting forum. the only work around seems to be not synchronizing the time. (past experience tells they do release updates when they come to know)

  2. I’m surprised to hear someone say the networks’ timekeeping is off. Before household “atomic” clocks (which are very accurate, when they can successfully update themselves often) became so prevalent, I built a Heathkit GC1000 “Most Accurate Clock”, which translates the time signal broadcast by NIST from Boulder, CO. My first observation was that the networks were dead on with their timekeeping. You truly could (and can still) set your clocks by the networks. I’ve found, too, that computer clocks are notoriously inaccurate when not updated frequently.

    I think it’s likely that the TV network clocks are dead-on correct. However the timing of their programming is another matter. I regularly lose the “tail” of TV shows that I know I’ve recorded from X:00 to X:59:59 on a correctly set box.


  3. With a laptop and desktop running Vista, only the laptop will syncronize internet time through my provider ( The desktop, regardless of which server I select, always gives me the same message (An error occurred while Windows was syncronizing with (etc.)). What is wrong with the desktop?

  4. When I click on the Task Bar clock, then select Adjust Date/Time, the pop up window does not have the Internet Time tab. It seems that I have the Plain Jane version. How do I get the Elegant Ellie version with the Internet Time tab?

    I suspect it depends on your version of Windows. I don’t think it was there in Windows 9x, for example.


  5. There is a program ,nistime-32bit, that queries the National Institute of Standards and Time (NIST) server and updates your computer clock. A google search for “nistime-32bit” should find the program.
    I did not know Windows updated the clock as Leo writes above. I checked and have this option active, but still once a month or so when I run nistime-32bit, my computer clock is always off by half a second or so.

  6. I use “AtomTime Pro” myself ( Works like a charm.

    I’m surprised to hear that the USNO keeps U.S. time — I thought that was the province of NIST? Oh, well…

    The main thing I wanted to say, is that once I’d installed AtomTime, and set my watch by it, I found that I could actually COUNT DOWN to the start of “Jeopardy!”, and my Mom always gets a kick out of it — the commercials would be going, the station announced, etc., and it would seem that it wasn’t going to make it, but ALWAYS, just after I would say “zero” — “This Is Jeopardy!” would boom out from our T.V.’s speaker! :)

    But, yes, I too have noticed that not ALL networks synchronize their programs to the exact time. Some run “early” or “late”. “Jeopardy!” simply happens to be, apparently, on a network (offhand I forget which one) which just happens to use “the precise time”. :)

  7. Thank You Ziggie! I found your answer to my problem further down the page, today 9-16-08. The time protocol port was setup in McAfee, however the inbound and outbound UDP ports had no numbers in them (123). Adding the 123 to each, allowed the time to be updated with no error message! Thanks Again! Mark

    Mark, see this link:
    that may help you.

    Posted by: Ziggie at September 10, 2008 08:33 AM

  8. I have GP policy for the time on the servers. Have a few computers not registering the right time. I reset it as local admin and it just goes back to the prior hour in a few minutes. What is up w/ that?

  9. The last posting is asking about the same problem I am having on my office network. I cannot find an answer on the web anywhere. Can someone help us both please.

  10. I’m on an office network and tried resetting as admin and a few other fixes. I finally resorted to changing my time zone from Central to Eastern and voila! I once again have the correct time. Cheers.


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