Here is a sample Webkit time value: 13066077007826684.

At first glance, it appears to be very similar to Unix epoch time, just slightly longer (perhaps it is storing nanoseconds?). An examiner who attempts to decode this as epoch time will get a date in May 2011, which may seem accurate, but is in fact several years off from the correct date!

Webkit time is an epoch time, it is just based on a different starting point than Unix epoch time. Webkit epoch time is the number of microseconds since midnight on January 1st, 1601. Yes, we said the year 1601. Once we know where the epoch begins, converting to a recognizable format simply becomes a math problem. But, once again, we'd rather use DCode.

This time in DCode, choose Google Chrome Value in the Decode Format dropdown selection, and click Decode:

The actual value of our example is November 2nd, 2014 at 18:04:33 UTC; significantly different than the value we would have come up with if we'd thought it was a Unix epoch time!