Unix time counts the seconds since 1 January 1970 at 00:00 UTC. Log entries, APIs and database rows mix that number with human-readable dates, so this converter works in both directions. It shows UTC, your local timezone, ISO 8601 and RFC 2822 at the same time.
Timestamp to date
- UTC
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- Local
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- ISO 8601
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- RFC 2822
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- Relative
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Date to timestamp
- Seconds
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- Milliseconds
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- ISO 8601
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How to read a Unix timestamp
A ten-digit number is almost always seconds, which takes until the year 2286 to overflow into eleven digits. A thirteen-digit number is milliseconds, the format JavaScript and many APIs use. The auto-detection switch treats values at or above one trillion as milliseconds, which is a safe rule for dates between 2001 and 33658.
A Unix timestamp is always UTC. It has no timezone of its own, so the same value reads as a different clock time depending on the viewer. That is why logs usually store the epoch value and render local time only in a user interface.
Common conversions
- Seconds to milliseconds: multiply by 1000. Milliseconds to seconds: divide by 1000 and drop the fraction.
- ISO 8601: the format with a T separator and a trailing Z, such as 2023-11-14T22:13:20Z. Many APIs require it instead of a bare epoch value.
- Dates before 1970: valid timestamps are negative. A value of -86400 is 31 December 1969 at 00:00 UTC.
Leap seconds and precision
Unix time ignores leap seconds: it treats every day as exactly 86,400 seconds, so it can drift by a second from astronomical time. For log ordering and cache expiry that does not matter. For precise measurements use a monotonic clock or the higher-resolution milliseconds shown above.
Date conversion uses your browser's timezone database. If you need a guaranteed timezone, convert from the UTC or ISO 8601 value on the right.