Unix Timestamp Converter
Convert Unix timestamps in seconds, milliseconds or microseconds to dates (and back) in UTC or any time zone, with ISO 8601, RFC 2822 and relative time. Free.
Numbers are read as seconds, milliseconds, microseconds or nanoseconds by their length (or pick the unit). Dates: ISO 8601 (without an offset the selected time zone is used) or RFC 2822.
What is Timestamp Converter?
Paste a Unix timestamp or a date and see it in every common form: Unix seconds, milliseconds and microseconds, ISO 8601 in UTC and in a chosen time zone, RFC 2822, a localized date, relative time, day of the year and ISO week. Timestamp units are detected from the number of digits.
How to use Timestamp Converter
- Enter a timestamp (
1700000000,1700000000123) or a date (2024-01-01T09:00:00+07:00,Tue, 14 Nov 2023 22:13:20 GMT), or press Now (s) / Now (ms). - Leave Timestamp unit on auto-detect or force seconds, milliseconds, microseconds or nanoseconds.
- Choose a Time zone (your browser zone, UTC or any IANA zone).
- Copy any of the result rows.
Example
1700000000 (UTC)
2023-11-14T22:13:20.000Z · Tue, 14 Nov 2023 22:13:20 +0000 · ms 1700000000000 · ISO week 2023-W46 · day 318
When to use Timestamp Converter
Use it to read timestamps in logs, databases, JWT claims or APIs, or to produce a timestamp for a given local time. Note that ambiguous local times during a DST change resolve to the first occurrence.
How Timestamp Converter works
Numbers are classified by digit count – up to 11 digits as seconds, 12–14 as milliseconds, 15–17 as microseconds, more as nanoseconds – and stored as BigInt nanoseconds so microsecond inputs keep full precision. ISO 8601 strings with Z or an offset are exact; without an offset they are interpreted as wall-clock time in the selected zone. Other strings such as RFC 2822 go through the browser's Date parser. Zone offsets come from the Intl API (IANA tz database), so daylight-saving time is handled; the localized date and relative time use Intl.DateTimeFormat and Intl.RelativeTimeFormat in the page language.
Common Use Cases
- Read the exp and iat claims of a JWT
- Convert a log timestamp in milliseconds to a readable date
- Find the Unix time of a meeting in another time zone
- Check which ISO week a date belongs to
- Debug off-by-one-hour bugs caused by time zones
FAQs
Seconds or milliseconds?
Unix tools and most databases use seconds (10 digits today); JavaScript and Java use milliseconds (13 digits). The tool detects the unit from the length and shows which one it used.
How are dates without a time zone handled?
An ISO date such as 2024-07-01T00:00 is read as local time in the selected zone, so 2024-07-01T00:00 in America/New_York is 1719806400.
Does it handle negative timestamps?
Yes, negative values are dates before 1970-01-01.
Is it affected by leap seconds?
No. Unix time ignores leap seconds by definition, and so does this tool.