Data tools

Unix timestamp converter

Auto detects seconds or milliseconds. You can override the unit.

Choose an input or use Current time.

Dates and time zones are processed in this browser, without upload or saved history.

Help & FAQs

Convert the current time with one click, choose a date on the calendar, or paste a Unix timestamp with automatic seconds/milliseconds detection. Copy either timestamp or download a local TXT report.

How to use

  1. Choose timestamp → date or date → timestamp.
  2. Paste a timestamp, pick a calendar date, or use Current time to convert immediately.
  3. Check the time zone and results, then copy seconds/milliseconds or download TXT.

Date, unit and time-zone rules

Timestamps are strict ASCII signed numbers; seconds accept up to three decimal places and milliseconds are integers. Dates use YYYY-MM-DD HH:mm[:ss[.SSS]] or T as separator, without a trailing zone suffix. The IANA field determines the input date zone or output date zone; UTC is the default.

Supported instants are from 1900-01-01T00:00:00.000Z through the end of 2100 UTC. At the boundaries, a zoned calendar date can fall in 1899 or 2101; the bound applies to the resulting UTC instant. Calendar overflow and leap seconds are rejected. Browser Intl supplies time-zone rules, which may differ by browser version and future legislation. A repeated local time requires an explicit earlier/later occurrence; a skipped local time is rejected.

Signed integer/decimal parsing preserves millisecond precision. Conversion samples native offsets around the date and verifies all wall-clock fields; it never silently uses the host time zone or normalizes gaps. Input is limited to 100,000 UTF-16 units / 400,000 UTF-8 bytes; timestamp syntax is bounded to 13 integer digits and date syntax is fixed. Processing yields with 45-second checkpoints. Results, copy requests and TXT URLs are invalidated on edits/cancellation/exit.

Common questions

How does automatic unit detection work?

Decimal values and integers with up to 10 significant digits use seconds; 11–13 significant digits use milliseconds. This convenience rule is shown below the input. Short millisecond values near the epoch are ambiguous: choose Milliseconds explicitly. Both units are always reported without losing millisecond precision.