Unix Timestamp Converter
Type a timestamp or a date and see the same moment in UTC, your time zone, KST, and JST.
Stays in your browserISO 8601RFC 3339RFC 2822As of 2026.10.03
Current Unix time—
Input
How to use Unix Timestamp Converter
- 1Type a timestamp such as 1767225600 or a date such as 2026-01-01 09:00:00, or press Sample.
- 2Leave Direction and Unit on Auto, or choose them yourself. Pick a time zone for dates that have no offset.
- 3Press the Copy button on the row you need.
Unix Timestamp Converter options
- Direction
- Auto reads input made only of digits as a timestamp, and anything else as a date. You can also fix the direction with To date or To timestamp.
- Unit
- Auto chooses by size: below 10^11 is seconds, below 10^14 milliseconds, below 10^17 microseconds, and anything larger nanoseconds. A badge shows how the value was read. Choose a unit yourself to override it.
- Time zone
- Used to read a date that has no offset, and for the locale format and the day of the week. The default is your browser's time zone. UTC, KST, and JST are always shown.
Unix time and the formats shown here
Unix time is the number of seconds since 1970-01-01T00:00:00Z, not counting leap seconds. POSIX defines it as seconds since the Epoch. It has no time zone: the same number means the same moment everywhere, and only the way it is written differs from place to place.
The ISO 8601 row follows the profile in RFC 3339 and always ends in Z (UTC). The RFC 2822 row is the format used in email headers and HTTP dates. The time zone rows use YYYY-MM-DD HH:mm:ss with the offset from UTC next to them.
Microseconds and nanoseconds keep every digit
A JavaScript Number cannot hold integers above 2^53 exactly, so a nanosecond timestamp such as 1767225600123456789 would lose its last digits if it were read as a Number. This tool does the arithmetic with integers of any size, so the fraction of a second in the ISO 8601 row matches the input digit for digit.
Dates without an offset
2026-01-01 09:00:00 does not say where it is 9 o’clock. This tool reads it in the time zone you select, which is your browser’s time zone unless you change it. In Asia/Seoul it becomes 1767225600, and in UTC it becomes 1767258000. When the input has an offset or Z, the selected time zone is not used.
Unix Timestamp Converter examples
Seconds to a date
Read as seconds. In KST and JST it is 2026-01-01 09:00:00.
Input
1767225600
Output
2026-01-01T00:00:00Z
Milliseconds to a date
Read as milliseconds, because the value is 10^11 or more.
Input
1767225600123
Output
2026-01-01T00:00:00.123Z
The last value of a 32-bit time_t
One second later a signed 32-bit integer overflows. This is the year 2038 problem.
Input
2147483647
Output
2038-01-19T03:14:07Z
A date to a timestamp (time zone: Asia/Seoul)
Input
2026-01-01 09:00:00
Output
1767225600
Examples use the reference cases this tool is tested against.
Unix Timestamp Converter: frequently asked questions
Is my input sent to a server?
No. Your input and the result are processed only in this browser and are not stored. Reloading the page clears them.
How does it tell seconds from milliseconds?
By the size of the number. A value below 10^11 is read as seconds, below 10^14 as milliseconds, below 10^17 as microseconds, and anything larger as nanoseconds. The badge above the result shows which one was used. If the guess is wrong, choose the unit yourself.
What is the year 2038 problem?
Systems that store time in a signed 32-bit integer can count up to 2147483647, which is 2038-01-19T03:14:07Z. One second later the value overflows. This tool adds a note for that value and for every value outside the 32-bit range.
Which date formats can I enter?
ISO 8601 (2026-01-01T09:00:00+09:00 or 2026-01-01T00:00:00Z), YYYY-MM-DD HH:mm:ss, a date alone (2026-01-01), and RFC 2822 (Thu, 01 Jan 2026 00:00:00 +0000). A date without an offset is read as a time in the selected time zone.
What range of dates is supported?
The same range as a JavaScript Date: 8,640,000,000,000,000 milliseconds before or after 1970-01-01T00:00:00Z, which is roughly the years -271821 to 275760. Values outside it are reported as out of range.
Related tools
How it works · Standards
- Processed in: this browser (your device). Nothing is sent or stored.
- Standards: ISO 8601 · RFC 3339 · RFC 2822
- Engine: Intl (browser built-in) (browser API) · ZEKILO Dev date parser and formatter (in-house code)
- Leap seconds are not counted, as in Unix time itself.
- A local time skipped by daylight saving time is moved forward by the gap. A local time that occurs twice is read as the earlier one.
- Relative time comes from the browser's Intl.RelativeTimeFormat, so its wording can differ slightly between browsers.
- As of 2026.10.03
- Changelog: 2026.10.03 First release