UnixTime
Convert Unix timestamps to readable dates and back, with timezone support. Everything is computed in your browser.
Timestamp → Date
- Date (selected zone)
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- UTC
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- ISO 8601
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- Relative
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Date → Timestamp
- Timestamp (seconds)
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- Timestamp (milliseconds)
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How Unix timestamps work
A Unix timestamp counts the seconds elapsed since January 1, 1970 at 00:00:00 UTC — the so-called "Unix epoch." It's independent of any timezone: it represents an absolute instant, and only when displaying it as a date do you choose which zone to interpret it in:
1755500000 (seconds) → UTC: 2025-08-18 06:53:20 → America/New_York: 2025-08-18 02:53:20 (UTC-4) → Asia/Tokyo: 2025-08-18 15:53:20 (UTC+9)
This tool uses the browser's native Date object and Intl.DateTimeFormat for the conversions — no external libraries, no server calls.
Frequently asked questions
What exactly is a Unix timestamp?
It's the number of seconds elapsed since January 1, 1970 00:00:00 UTC (the "Unix epoch"), independent of timezones and leap seconds.
Does it work with seconds or milliseconds?
Both: there's a toggle to say whether the timestamp you pasted is in seconds (Unix standard, ~10 digits) or milliseconds (used by JavaScript, ~13 digits).
How does it handle timezones?
A Unix timestamp is always the same absolute instant in time; the timezone only changes how that instant is displayed. You can pick any IANA zone to see the corresponding local date.
Is the date-to-timestamp conversion accurate with timezones?
Yes for the vast majority of cases. It uses the browser's native Intl APIs; right at a daylight-saving transition there can be a one-hour ambiguity, which is inherent to how civil calendars work, not a bug in the tool.