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Unix Timestamp Converter

Converts between Unix epoch timestamps and human-readable UTC or ISO date-times in seconds or milliseconds.

100% FreeRuns in your browserBasic
How to use this calculator

Input

Convert

Blank = now. ISO 8601, e.g. 2026-01-01T00:00:00Z; without Z or an offset it is read in the zone above.

Result

Enter a timestamp.

Unix time counts from 1970-01-01T00:00:00Z and ignores leap seconds. Time-zone rules come from your browser and may lag recent changes.

Runs entirely in your browser. Your input is not uploaded or stored.

How the method works

One instant, many wall-clock readings
Illustrative method
One instant, many wall-clock readingsA vertical line marks the instant Unix time 0. It crosses three time-zone rows: UTC reads 1970-01-01 00:00:00, Australia/Perth reads 08:00 the same day and America/New_York reads 19:00 on 31 December 1969.epoch 0 sUTCUTC+00:001970-01-01 00:00:00Australia/PerthUTC+08:001970-01-01 08:00:00America/New_YorkUTC−05:001969-12-31 19:00:00Same instant → same epoch, different local text
Unix time 0 seconds (= 0 ms = 0 ns) is the instant 1970-01-01T00:00:00Z. Shown in Australia/Perth (UTC+08:00) it reads 1970-01-01 08:00; in America/New_York (UTC−05:00) it reads 1969-12-31 19:00. The time zone changes the wall-clock text, never the epoch number.

Unix time counts seconds from 1970-01-01T00:00:00Z and ignores leap seconds; the time zone only changes how an instant is written. Fixed example values for illustration — not your result.

How to use this calculator

  1. Timestamp to date: enter the epoch and choose its unit — seconds, milliseconds, microseconds or nanoseconds. A digit-count hint suggests a unit, but you confirm it.
  2. Date to timestamp: enter an ISO 8601 date-time with Z or an offset, or a local time read in the chosen time zone.
  3. Read the UTC ISO value, the time in your chosen zone with its offset and weekday, every unit, and the time relative to now — or to a reference time you type.

How it works

Unix time counts from 1970-01-01T00:00:00Z. The epoch is handled as an exact decimal, so microseconds and nanoseconds are never rounded away; negative values are dates before 1970.

A time zone changes how an instant is shown, never the epoch. A local time repeated when clocks go back offers both offsets; one skipped when they go forward is reported, not shifted.

Unix time ignores leap seconds, so :60 is rejected with that explanation. Zone rules come from your browser.

Worked example

0 and 1 ns. 0 seconds = 1970-01-01T00:00:00Z; −1 second = 1969-12-31T23:59:59Z; 1 nanosecond = 1970-01-01T00:00:00.000000001Z.

Common mistakes

  • Guessing seconds vs milliseconds — a 13-digit value read as seconds lands tens of thousands of years away.
  • Typing a local time without choosing its zone.
  • Assuming a DST-repeated time is unambiguous.

Tips

  • Runs entirely in your browser. Your input is not uploaded or stored.

Frequently asked questions

Seconds or milliseconds?

You choose the unit. The tool suggests one from the number of digits, but never applies it silently.

Privacy?

Runs entirely in your browser. Your input is not uploaded or stored.

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Cite this tool

Zerdly. (2026). Unix Timestamp Converter. Retrieved from https://www.zerdly.com/tools/unix-timestamp-converter/

Tip: Enter any known values to calculate the remaining results.

Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.