What a Unix timestamp is
A Unix timestamp counts the seconds that have passed since midnight UTC on 1 January 1970, a moment known as the epoch. Because it is a single number with no time zone attached, it is an easy way for systems to store and compare moments in time. The value 0 is the epoch itself, and 86400 is exactly one day later.
Many systems use milliseconds instead of seconds, which makes the number three digits longer. A seconds timestamp today has ten digits, while a millisecond one has thirteen. Mixing the two up is one of the most common sources of dates that land in 1970 or in the far future.
When you need to convert them
Timestamps appear in database rows, log files, API responses, cookies, authentication tokens and file metadata. They are great for machines but unreadable for people, so you convert them to check when something happened, to compare two events, or to work out the number to put into a query or a test.
Going the other way, you pick a date and time and get the number to use in a configuration or an API request. If you are inspecting a login token, the JWT Decoder shows its claims, and exp or iat values inside it are Unix timestamps you can paste here. A separate page, the Unix Time Converter, offers the same conversions.
How to use this converter
- The Current Unix time panel shows the present time in seconds, updating every second. Click Use this to copy that value into the converter below.
- In the Timestamp to date section, type or paste a timestamp. If it has more than ten characters it is read as milliseconds; otherwise it is read as seconds.
- The result shows three lines: Local (your device's time zone), UTC, and ISO 8601.
- In the Date to timestamp section, pick a date and time with the picker. The number of seconds since the epoch appears below it.
All of this runs in your browser using your device's clock. Nothing is uploaded.
Tips and limits
The seconds-or-milliseconds choice is made purely by length. A timestamp of more than ten characters is treated as milliseconds, and anything shorter as seconds. A negative number counts its minus sign as a character, and very small values are read as seconds, so dates well before 1970 or unusual values may not behave as you expect. If a date looks wrong, check whether your source uses seconds or milliseconds.
The date picker interprets what you choose in your device's local time zone, then shows the equivalent timestamp in seconds. Two people in different zones picking the same clock time will therefore get different numbers. When it matters, compare against the UTC line. The picker's starting value is based on the current UTC clock reading, so when you first open the page it may differ from your local time by your zone's offset.
The date-to-timestamp side returns whole seconds only, with no milliseconds, and the page does not offer other time zones or a download.