Date Tools

Unix timestamp converter

Convert epoch seconds or milliseconds to UTC, or turn an exact UTC date and time into a timestamp.

Convert a timestamp

UTC only · 1600–2399 · no automatic unit detection

Whole seconds: -11676096000 to 13569465599. Negative values are before 1970.

Inputs and results stay in this page’s memory.

Your conversion

From a log entry to UTC

Choose the unit used by your API, database or log, then enter its integer timestamp. Or switch to convert an exact UTC date and time.

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Read the time behind a number

  1. Choose Timestamp to UTC or UTC to timestamp.
  2. For a timestamp, explicitly choose Seconds or Milliseconds. We never guess from the number of digits.
  3. Convert, then copy the UTC time, epoch milliseconds and whole epoch seconds.

A Unix timestamp counts time since January 1, 1970 at 00:00:00 UTC. Check the unit your log, database or API uses before comparing values.

Known examples: 0 seconds → 1970-01-01T00:00:00.000Z. 1700000000 seconds → 2023-11-14T22:13:20.000Z. −1 millisecond → 1969-12-31T23:59:59.999Z.

For calendar tasks, use Age on a date, Date difference or Add / subtract days.

Units, UTC and precision

Seconds or milliseconds?

One second is 1000 milliseconds. The same number can be valid in both units: 1700000000 milliseconds means 1970-01-20T16:13:20.000Z. The selected unit determines the conversion. If the result is outside 1600–2399, check the unit; we do not switch it automatically.

What UTC text is accepted?

Use YYYY-MM-DDTHH:mm:ssZ or YYYY-MM-DDTHH:mm:ss.SSSZ, with exactly three optional millisecond digits and uppercase T and Z. For example, 2000-02-29T12:34:56.789Z is valid. Spaces, timezone offsets, leap second 60 and 24:00 are not accepted. Dates must exist in the Gregorian calendar from 1600 through 2399.

How are negative and fractional seconds handled?

Negative timestamps are before the Unix epoch. Inputs must be whole seconds or whole milliseconds; decimals, exponents, plus signs and leading zeros are rejected. The output whole seconds use floor, toward negative infinity: −1 millisecond gives −1 second. Whole seconds cannot preserve a partial second.

Does the local timezone change the answer?

No. Both directions use UTC only. This tool does not convert local time, select timezones, handle microseconds or nanoseconds, or import batches. Use current time takes one snapshot when clicked; it does not run a clock in the background.

Are timestamps or results saved?

No. Inputs and results stay in this page’s memory, and clear when you leave. They are not added to the URL, browser storage, analytics or feedback automatically.