Unix Timestamp Converter
A Unix timestamp counts seconds since January 1, 1970 UTC. Paste a timestamp to see the date, or pick a date to get its timestamp — in UTC or any time zone.
Timestamp → Date
10 digits = seconds, 13 digits = milliseconds
Date → Timestamp
How Unix time works
Unix time starts at the "epoch": midnight UTC on January 1, 1970. Every second since then increments the count by one. Because it is a single number with no time zone, calendar, or formatting attached, it is the standard way computers store and exchange moments in time — in databases, APIs, log files, and file metadata.
The converter above reads the timestamp as UTC, then displays it either in UTC or converted to your browser's local time zone. When converting a date back to a timestamp, the input is interpreted as UTC to keep the round-trip exact.
Worked examples
- 0 → January 1, 1970, 00:00:00 UTC (the epoch itself).
- 1000000000 → September 9, 2001, 01:46:40 UTC — the first 10-digit timestamp, celebrated by programmers.
- 2147483647 → January 19, 2038, 03:14:07 UTC — the maximum 32-bit signed value.
Edge cases
- Milliseconds vs seconds: JavaScript's
Date.now()returns milliseconds (13 digits). Divide by 1,000 for the classic timestamp. - Negative timestamps represent dates before 1970 and work fine.
- Far-future dates beyond 2038 need 64-bit storage; this converter handles them.
Frequently asked questions
What is a Unix timestamp?
A Unix timestamp is the number of seconds that have passed since 00:00:00 UTC on January 1, 1970 (the "epoch"). For example, 1000000000 corresponds to September 9, 2001 at 01:46:40 UTC. It is a compact, time-zone-free way to represent a moment in time.
Seconds or milliseconds?
Classic Unix timestamps count seconds. JavaScript's Date.now() returns milliseconds — 1,000× larger. This converter accepts both: 10-digit values are treated as seconds, 13-digit values as milliseconds. If you paste a millisecond value, the converter handles it automatically.
What is the Year 2038 problem?
Systems that store timestamps as a signed 32-bit integer overflow at 03:14:07 UTC on January 19, 2038 (timestamp 2147483647). Modern 64-bit systems are unaffected. This converter handles the full 64-bit range, so you can convert dates far beyond 2038.
Do Unix timestamps account for leap seconds?
No. Unix time pretends every day has exactly 86,400 seconds, ignoring leap seconds. This means Unix timestamps drift from true astronomical time by the accumulated leap seconds (currently 27). For everyday use this does not matter.
Why does my timestamp show a different date than expected?
Almost always a seconds-vs-milliseconds mixup, or a time-zone display issue. The timestamp itself is always UTC. If your code shows a different local date, check whether your display is converting to your local time zone — the underlying moment is the same.
Related tools
Conversions are computed in your browser using the IANA time zone database. No data leaves your device.