Timestamp

A timestamp is a numeric value indicating a number of units of time (usually seconds or milliseconds) that have elapsed since an initial date named Epoch, equal to 0.

A timestamp is calculated from the initial date. By default, each second after this date increments the timestamp with 1 unit.

The most popular Epoch is January 1, 1970 for Unix operating systems, Java programming languages, PHP, C ++, etc.

Epoch is January 6, 1980 for GPS (first Sunday of the year 1980)

A timestamp allows comparison of two dates in an fast, exact and sure way. Indeed, with daylight saving time change, sometimes a 2h59 in the morning plus one minute, suddenly it is 2h00, the comparison of times is therefore difficult.

dCode's converter allows to convert automatically by calculating exact days, months, years, hours, minutes and seconds (depending on the time zone).

The dates in Excel have their own Epoch (January 0, 1900), the trick is to remove the one from Unix.

The converting trick is to add the date Epoch of Unix/Linux =A1/86400+DATE(1970,1,1)

January 1st, 1970 00:00 UTC is the start of UNIX era.

On the 19/01/2038 at 03:14:07, the number of seconds since Epoch Unix will be 2147483647 seconds: 2^31-1, this is the size limit for 32bits systems. There will be a bug on the next second when calculating dates on these systems and all future dates will be considered in the past by the system.