Timestamp Converter

The number of seconds that have elapsed since midnight UTC on 1 January 1970, a moment known as the epoch. It is how most software stores a point in time, because a single integer has no timezone, no locale and no ambiguity about date order.

Count the digits. A current timestamp in seconds has ten; in milliseconds it has thirteen. Unix tools, PHP and most databases use seconds, while JavaScript and Java use milliseconds. Feeding milliseconds to something expecting seconds lands you tens of thousands of years in the future, which is a very common bug.

Because a timestamp is an absolute instant and a date is a local reading of it. A timestamp near midnight UTC falls on the previous or next calendar day depending on where you are. Check whether the value you are comparing against is UTC or local before assuming something is broken.

A signed 32-bit integer counting seconds overflows on 19 January 2038, wrapping to a negative number and landing in 1901. Modern systems use 64-bit timestamps and are unaffected, but embedded devices, old file formats and legacy databases can still be exposed.

Click Use Current Time and it fills in this moment, ready to convert or copy. It is the quickest way to get a reference value when you are debugging something time-related.

It was a round, recent date when Unix was being developed in the early 1970s, chosen so a 32-bit counter would cover a useful span in both directions. There is nothing significant about the date itself; it simply became the convention everything else inherited.