Timestamp Converter

Runs in browser Utilities

Paste an epoch timestamp or a date string and get ISO 8601, RFC 2822, local time, UTC, relative time and the epoch in seconds/milliseconds/nanoseconds. Auto-detects the unit.

Privacy: This tool runs entirely in your browser. Your input never leaves your device.

What is an ISO 8601 timestamp, and how does it relate to Unix time?

ISO 8601 writes a moment as 2026-09-23T10:15:00+03:00 — largest unit first, with an explicit UTC offset or Z — so it sorts as text and is unambiguous across locales; RFC 3339 is the Internet profile APIs use. Unix time is the same moment as a count of seconds (or milliseconds in JavaScript) since 1970-01-01T00:00:00Z, with no time zone at all. Most date bugs are an offset applied twice or a local time stored as if it were UTC.

One instant, three notations: Riyadh wall-clock time with its +03:00 offset, the same moment in UTC with Z, and a count of Unix seconds that has no time zone at all.

ISO 8601 (Asia/Riyadh)

Part 1:2024-03-15TPart 2:13:30:00.000Part 3:+03:00

ISO 8601 (UTC)

2024-03-15TPart 4:10:30:00.000Part 5:Z

Seconds

Part 6:1710498600

  1. 1Calendar date, largest unit firstYear, month, day: the text sorts in time order.
  2. 2Wall-clock time at that offsetWhat a clock in Riyadh shows: 13:30.
  3. 3UTC offsetThe difference from UTC in hours and minutes, not a zone name; the tool derives it for this instant from Asia/Riyadh.
  4. 4The same moment in UTCSubtract the offset once: 13:30 − 03:00 = 10:30.
  5. 5Z: UTC, offset zero
  6. 6Seconds since 1970-01-01T00:00:00ZNo time zone at all. JavaScript counts milliseconds:1710498600000

Values are the tool’s output for the example 1710498600 in Asia/Riyadh. Subtracting the offset a second time gives 07:30: the offset-applied-twice bug.

How to use Timestamp Converter

  1. Paste a timestamp or a date string.
  2. Leave the unit on Auto-detect or choose one explicitly.
  3. Select the timezone in which you want to read the result.
  4. Copy any of the formats or the epoch values.

Timestamp Converter features

  • Auto-detects seconds, milliseconds, microseconds and nanoseconds
  • Accepts ISO 8601, RFC 2822, "now" and common date strings
  • ISO (UTC and zoned), RFC 2822, human-readable local and UTC, relative time
  • Epoch in s, ms, µs and ns; weekday, day of year, ISO week, quarter and leap-year flag
  • Any IANA timezone with the current offset and abbreviation
  • Live conversion and a one-click "Use current time"

Timestamp Converter example

Epoch seconds to Riyadh time

Input:

1710498600 · Asia/Riyadh

Output:

Friday, 15 March 2024 at 13:30:00 GMT+3
ISO (UTC): 2024-03-15T10:30:00.000Z
RFC 2822: Fri, 15 Mar 2024 13:30:00 +0300

Frequently asked questions about Timestamp Converter

How does the unit auto-detection work?

By magnitude: values below 10^11 are seconds, below 10^14 milliseconds, below 10^17 microseconds and anything larger nanoseconds. Override it with the unit selector when converting historic or far-future dates.

Which date formats are accepted?

Epoch numbers, ISO 8601 / RFC 3339 (2024-03-15T10:30:00Z, with offsets and fractions), RFC 2822 (Fri, 15 Mar 2024 10:30:00 +0300), the word "now" and most formats the browser can parse.

What timezone is used for strings without an offset?

The timezone selected in the tool (your local zone by default). Add Z or +03:00 to the string to make it unambiguous.

Why is the nanosecond value padded with zeros?

JavaScript dates have millisecond precision. Microsecond and nanosecond outputs are exact multiples of the millisecond value; sub-millisecond digits from your input are not preserved.

Technical notes

All calendar arithmetic uses Intl.DateTimeFormat.formatToParts for the selected zone; offsets are derived by comparing the zoned wall-clock time with the UTC instant, which correctly reflects daylight-saving rules without any bundled timezone database.

References