This clock provides a convenient way to synchronize wristwatches and portable timing devices to a known time standard.
The accuracy of the displayed time depends entirely on your computer's clock accuracy. This page has no independent time reference.
Fortunately, many modern operating systems periodically and automatically synchronize their clocks with network time standards.
To find out whether your computer is synchronized with a reference standard, tune a shortwave radio to time reference stations WWV (Fort Collins, Colorado) or WWVH (Honolulu, Hawaii), at 2.5, 5, 10, 15 or 20 MHz, depending on time of day, and compare the above display to the received radio time signals.
If your operating system isn't time-synchronized, you have some options:
Find out how to add this important feature to your existing OS.
Dump your present OS (it's most likely Windows) and install Linux, which does have the described feature.