Date & time

Unix timestamp converter: seconds, milliseconds & UTC

Convert Unix seconds, milliseconds and dates with explicit time zones. Compare UTC and local time, with examples for unit mistakes and 1970 dates.

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How to use

Choose seconds or milliseconds. Use ISO 8601 with an explicit time zone for dates, such as 2026-09-07T08:00:00Z.

Your input stays yours

Step by step

For numeric input, select Seconds or Milliseconds first. Do not rely on digit count alone to infer the unit.
Enter a timestamp, or a date with Z or a time-zone offset, such as 2026-09-07T16:00:00+08:00.
Choose Convert to compare seconds, milliseconds, UTC and local time. Local output follows the current device’s time-zone settings.

Try it: four representations of one instant

Unix (s):  1788768000
Unix (ms): 1788768000000
UTC:       2026-09-07T08:00:00.000Z
UTC+08:00: 2026-09-07T16:00:00+08:00

Paste one value at a time. Multiply seconds by 1000 for milliseconds. This tool floors the Unix (s) output, so that field does not retain the millisecond fraction.

Frequently asked questions

Are timestamps 10 or 13 digits?

Recent dates often use 10-digit seconds or 13-digit milliseconds, but this is not universal. Values near 1970, negative values and distant dates have different lengths. Follow the API field definition; this tool does not guess units.

Why does the result show 1970?

A common cause is interpreting seconds as milliseconds. Selecting Milliseconds for 1788768000 produces a date in 1970. Verify the input unit first; treating milliseconds as seconds produces a distant date or an out-of-range error.

Should I change the timestamp for an eight-hour UTC offset?

No. One instant has the same timestamp regardless of how it is displayed. 08:00Z and 16:00+08:00 represent the same instant. Correct source data only after confirming that its time-zone annotation is wrong.

Why is a date such as 2026-09-07 rejected?

This tool requires a time and explicit offset to avoid browser-dependent interpretation. Use 2026-09-07T00:00:00Z, or supply the intended time and offset. Impossible dates such as 2026-02-30 are also rejected.