Unix Timestamp Converter
Convert a Unix timestamp to a date and time in UTC, or a date to a timestamp.
Good to know. On 19 January 2038, 32-bit Unix time runs out of seconds. Most systems have already moved to 64 bits.
How it works
In plain words
Unix time counts the seconds since midnight UTC on 1 January 1970, the Unix epoch, ignoring leap seconds. Every day is exactly 86,400 seconds, so a date is the number of whole days since then times 86,400, plus the seconds since midnight.
The formula
timestamp = days since 1970-01-01 × 86,400 + seconds since midnight UTC milliseconds = seconds × 1,000
Worked example
1767225600 seconds after the epoch is 20,454 days of 86,400 seconds: Thursday, January 1, 2026, 00:00:00 UTC.
Sources
No outside data or rates: this is plain arithmetic.
6 automated tests check its answers on every change.
About the unix timestamp converter
A Unix timestamp is the number of seconds since 00:00:00 UTC on 1 January 1970, called the Unix epoch. Computers, databases, logs and APIs store time this way because a single number is easy to compare, sort and do arithmetic on. This converter turns a timestamp into a readable date and time, or a date into a timestamp.
Timestamps are always in UTC, so they mean the same moment everywhere. To see the local time, add your time zone’s offset: the time zone converter does that. Many systems, including JavaScript and Java, count in milliseconds instead of seconds; a 13-digit number is read as milliseconds.
Unix time ignores leap seconds: every day counts as exactly 86,400 seconds. Negative timestamps are dates before 1970. Systems that store the time as a signed 32-bit number can only count to 2,147,483,647, which is 03:14:07 UTC on 19 January 2038, the “year 2038 problem”. Modern systems use 64 bits, which lasts for billions of years.
The ISO 8601 format shown, like 2026-01-01T00:00:00Z, is the standard way to write a date and time as text; the Z means UTC.
Questions people ask
What is the Unix epoch?
Midnight UTC on 1 January 1970, when Unix time is 0. Timestamps count the seconds since then.
How do I tell if a timestamp is in seconds or milliseconds?
Current timestamps in seconds have 10 digits; in milliseconds, 13.
What happens in 2038?
Signed 32-bit timestamps overflow at 03:14:07 UTC on 19 January 2038. Systems using 64-bit time are unaffected.