time.curby.net Web Clock

The clocks above represent the time on the curby.net server and on your client (browser).

Your client’s time zone is given as both an offset from GMT, and as an abbreviated time zone name. (UTC is not a time zone and is therefore not used as a basis for time zone offsets.)

The difference between the server and client clocks is labeled offset.

The path delay, or network latency, between the server and client is labeled delay.

On the home page, an offset of under a second will trigger a green notification message, an offset of 1-60 seconds will trigger a yellow message, and an offset of over a minute will trigger a red message.

This page is intended as an informal time of day service, and not for rigorous timing or clock synchronization.

See the accuracy and precision notes below for more information.

In layman’s terms, accuracy is how closely a clock matches an accepted reference clock. The live clocks on this site are meant to represent the time on a curby.net time server, and their accuracy is dependent on a variety of factors.

1. First, there is varying path delay, or network latency, between the server and your browser. This is largely corrected by timestamps sent between the client and server, but these timestamps in themselves can be inaccurate.
2. There is also processing delay on both the server and client. While such processing doesn’t take much time, it may add several milliseconds depending on workload.
3. After getting an initial reading of the time from the server, the “server time” is actually derived from the local time and an offset. If the local clock drifts, the displayed server time will also drift over time until it syncs to the server once again.

Bottom line: The live clocks on this site are generally within a decisecond of the server’s true time, but this is not a guarantee!

In layman’s terms, precision is the smallest chunk of time that a clock can represent. The precision of the live clocks on this site depends on the significant figures in the display and the code that governs how time is handled and displayed.

The code represents time with millisecond precision, but several factors limit the precision of the displayed time:

1. The update interval is significantly longer than a millisecond. For example, a clock that updates every 25 ms cannot resolve a smaller time duration.
2. Most computer and smartphone displays take 16 ms or longer to refresh. As update interval is decreased, the display itself becomes the limiting factor.
3. Lastly, the clocks above are set to display centisecond (10 ms) resolution, so precision can never improve beyond that.

Bottom line: The home page clock has second precision, and the clocks above show centiseconds but have lower actual precision that depend on the factors above.

• NTP Glossary on ntp.org
• Accuracy and Precision (Wikipedia)

Write to time@curby.net with any questions or concerns.