Unix timestamp converter
Paste an epoch number and see the date in UTC and in any time zone, or pick a date and get the timestamp. It guesses the unit, explains daylight saving oddities, and converts a list line by line. Nothing is uploaded; it all runs in your browser.
Right now
Seconds
…
Milliseconds
…
Timestamp to date
Paste a number such as 1700000000. Decimals, a minus sign and commas are fine.
Read as Seconds, guessed from the size of the number.
- Seconds
- 1700000000
- Milliseconds
- 1700000000000
- ISO 8601 (UTC)
- 2023-11-14T22:13:20Z
- In UTC
- 2023-11-14T22:13:20+00:00
- Offset from UTC
- UTC+00:00
- RFC 2822 style
- Tue, 14 Nov 2023 22:13:20 +0000
- Day of the week
- Tuesday
- Day of the year
- 318
- ISO week
- 2023-W46
Relative time is rounded and uses average month and year lengths, so treat it as an estimate.
The guess: under 100 billion is seconds, under 100 trillion is milliseconds, under 100 quadrillion is microseconds, anything larger is nanoseconds. It can be wrong for dates close to 1970 in milliseconds; pick the unit yourself if the date looks off.
Date to timestamp
This local time happens exactly once in UTC.
- Seconds
- 1700000000
- Milliseconds
- 1700000000000
- ISO 8601 (UTC)
- 2023-11-14T22:13:20Z
- Offset from UTC
- UTC+00:00
Convert many at once
Uses the unit and time zone chosen above. Each line is read on its own.
| Input | Unit | UTC | In the chosen zone |
|---|---|---|---|
| 1700000000 | Seconds | 2023-11-14T22:13:20Z | 2023-11-14T22:13:20+00:00 |
| 1700000000123 | Milliseconds | 2023-11-14T22:13:20.123Z | 2023-11-14T22:13:20.123+00:00 |
| -86400 | Seconds | 1969-12-31T00:00:00Z | 1969-12-31T00:00:00+00:00 |
The year 2038 limit
The largest signed 32-bit integer is 2147483647, which is 2038-01-19T03:14:07Z. One second later, a program that keeps seconds in a 32-bit signed integer wraps around to -2147483648, which is 1901-12-13T20:45:52Z. Many current systems use 64 bits and are not affected; it depends on how each program stores time.
Supported range is years 0001 to 9999 in the Gregorian calendar. Time zone rules come from your browser, which knows the history of each zone (including old local mean times). Everything is calculated on this page and nothing is uploaded.
How it works
- •A Unix timestamp counts the time since 1 January 1970 00:00 UTC. The number has no time zone in it; the zone only matters when you turn it into a readable date.
- •The unit is guessed from the size of the number: under 100 billion is read as seconds, then milliseconds, microseconds and nanoseconds as it grows. You can override the guess, which matters for millisecond values near 1970.
- •Zone offsets come from your browser's built-in time zone data, so the converter follows each zone's real rules, including half-hour zones and old local mean times. No date library is involved.
- •A local time can be skipped (clocks jump forward) or repeated (clocks go back). The converter tells you which case you are in, which offset it used, and shows the other reading so you can choose.
Questions
- How do I know if a timestamp is in seconds or milliseconds?
- Count the digits. A recent date is about 10 digits in seconds and 13 in milliseconds. The tool applies that rule automatically and tells you which unit it picked, and you can set the unit yourself if the result looks wrong.
- What happens to a time that does not exist because of daylight saving?
- When clocks jump forward, some local times never happen. The tool says so, uses the offset you choose (before or after the change) and shows the other possible timestamp. When clocks go back, a time happens twice and the same choice picks the earlier or later one.
- What is the year 2038 problem?
- A signed 32-bit integer holds seconds up to 2147483647, which is 19 January 2038 03:14:07 UTC. Software that stores time that way overflows after that. Systems that use 64-bit values are not affected.
- Is anything sent to a server?
- No. The conversion uses your browser's own date and time zone features, and the numbers you type stay on this page. The supported range is the years 0001 to 9999.