National Physical Laboratory

Why do you not have a time display on your website?

There are difficulties in displaying the time of day on internet pages. Because the transmission of page content is a one-way process, the propagation delay across telecoms networks from the server to the user's PC cannot easily be measured and corrected. This delay is generally a few seconds although it can vary significantly depending on the path taken by the data packets, and is apparent when the web page is compared with a more accurate source of time.

There are other methods to obtain the time more accurately via the internet. In particular, the network time protocol (NTP) allows time to be transmitted typically to within a tenth of a second and is widely used to synchronise computers to internet time servers. For more information, click here.

You will find our NTP servers for broadband users at and

Last Updated: 13 Apr 2010
Created: 13 Apr 2010


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