Convert a Unix timestamp into a readable date, or pick a date and get the timestamp. Seconds and milliseconds are detected automatically, and the live current timestamp is shown at the top.
How to use this tool
- Type a timestamp, or pick a date and time.
- The other field updates automatically.
- Every common format is listed below — click to copy any of them.
Seconds or milliseconds?
Unix time counts from 1 January 1970 UTC. The ambiguity that catches people out is the unit:
- Seconds — 10 digits today. Used by Unix tools, PHP, Python's
time(), JWTexpclaims, and most APIs. - Milliseconds — 13 digits. Used by JavaScript's
Date.now()and Java.
If you feed milliseconds to something expecting seconds, you get a date around the year 55,000. If you do the reverse, you land in January 1970. This tool disambiguates by magnitude, which is unambiguous for any realistic date.
Formats explained
- ISO 8601 —
2026-08-10T12:00:00.000Z. The right choice for APIs, logs, and anything stored. Sorts correctly as a string. - UTC — the same instant expressed in Coordinated Universal Time
- Local time — the same instant in your browser's timezone
- Relative — "in 3 days", "2 hours ago"
A timestamp always represents one instant. The local and UTC readouts are two labels for that same moment, not two different times.
Related tools
- Date difference calculator — measure a span between dates
- JWT decoder —
expandiatare Unix timestamps - Age calculator — elapsed time in years
- Unit converter — for measurements rather than time
FAQ
Is my data sent to a server?
No. Conversion uses the browser's own Date object.
What is the year 2038 problem?
Systems that store Unix time in a signed 32-bit integer overflow on 19 January 2038. Modern 64-bit systems are unaffected, but legacy embedded software and old database columns can still be at risk.
Why does my timestamp show a different time than my colleague's?
Because "Local time" reflects each viewer's own timezone. The ISO 8601 and UTC rows are identical for everyone — use those when comparing.
Can timestamps be negative?
Yes. A negative Unix timestamp is a date before 1970. This tool accepts them.
Does it handle leap seconds?
Unix time deliberately ignores leap seconds — it assumes every day is exactly 86,400 seconds. That is a property of the format itself, not of this converter.
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