Toolflux

Unix timestamp converter: Unix, ISO 8601 and 12 calendars

Unix timestamp converter with 16 readings: Unix, ISO 8601 and 12 calendar/date notations - Julian Day, Mayan, Hijri, Thai Buddhist, Ethiopian, Indian Saka and more. Y2038 warning. Local in your browser.

An instant is always the same instant - the name for it depends on the system. The converter below renders your moment in sixteen notations at once: Unix seconds for machines, ISO 8601 for JSON, Julian Day for astronomers, Mayan Long Count for history threads, Hijri / Thai / Ethiopian / Saka for national and religious contexts. Plus a Y2038 banner when your value crosses the 32-bit boundary.

Live - ticking · UTC (UTC)
20 : 03 42
Wednesday, May 6, 2026 · ISO week 19 · UTC+00:00
Shift
The same instant in 16 systems
Machine-readable For code, JSON, logs, databases.
Unix seconds
1778097822 Ticks every second since 1970-01-01 00:00 UTC.
Unix milliseconds
1778097822900 JavaScript's Date.now(). Three more digits than seconds.
ISO 8601 / RFC 3339
2026-05-06T20:03:42.900Z RFC 3339 is the strict variant: sorts as a string, unambiguous via offset.
Human-readable For UI copy, emails, conversation.
UTC and local
May 6, 2026 at 08:03:42 PM UTC May 6, 2026 at 08:03:42 PM UTC Wednesday · ISO week 19 UTC stays put through summer. Local shifts.
Relative
now Language instead of a number. Great for feeds, bad for logs.
Calendars and history Nine readings from astronomy, religion and tradition.
Japanese era
May 6, 8 Reiwa Reiwa means 'beautiful harmony'. Began May 1, 2019 with Emperor Naruhito.
Chinese
Third Month 20, 2026(bing-wu) 60-year cycle of 12 animals × 5 elements. Fire Horse since 17 February 2026; Wood Snake before that.
Islamic (Hijri)
Dhuʻl-Qiʻdah 19, 1447 AH ≈354 days per year. So holy days drift through the solar year.
Thai Buddhist Era
May 6, 2569 BE BE = Gregorian + 543. Year 1 traditionally marks the Buddha's parinirvana.
Indian National (Saka)
Vaisakha 16, 1948 Śaka Official since 22 March 1957. Year starts on 1 Chaitra: Saka = Gregorian − 78 from 22 March (21 March in leap years); before the rollover, − 79.
Ethiopian
Miazia 28, 2018 EC Twelve 30-day months plus Pagumē (5 or 6 days). Sits about 7 years 8 months behind Gregorian.
Julian Day Number
2461167 Invented 1583 by Joseph Scaliger - named after his father Julius.
Mayan Long Count
13.0.13.10.4 13 bʼakʼtun = 1,872,000 days. Next rollover: roughly year 4772.
French Republican
15 Floréal CCXXXIV 10-day weeks, 10-hour days. Napoleon abolished it in 1806.
Fictional Star Trek and Principia Discordia, because it's fun.
Stardate (Star Trek)
-296646.6 1000 stardate units = 1 year. The clock starts at zero in 2323.
Discordian
Discord 53, 3192 YOLD Sweetmorn 5 seasons of 73 days each, plus St. Tib's Day in leap years (off-grid).

The result explained

One instant, sixteen readings. Unix epochs for machines, ISO 8601 for humans-and-machines, classical and ethnographic calendars for context.

Runs in your browser. No network call. No account.

Three notations for machines, one for humans

The top "machine-readable" group has the three readings that drop straight into code:

  • Unix seconds. The POSIX standard. time(NULL) in C, Time.now.to_i in Ruby. A number like 1746576000.
  • Unix milliseconds. JavaScript native (Date.now()), Java (System.currentTimeMillis()), many newer APIs. Three digits longer than seconds.
  • ISO 8601 / RFC 3339. The human-and-machine standard. 2026-05-07T13:45:00+02:00 in your selected timezone, or 2026-05-07T11:45:00Z when UTC is selected. The right call in JSON - unambiguous because of the offset.

Just below, in the "human-readable" group, sits UTC and local: UTC rendered unambiguously plus the local time with weekday, DST marker, and ISO week number - the card you forward to a colleague.

If you only remember one notation: ISO 8601 with explicit offset. Unambiguous, sortable, understood everywhere.

Niche cards for context

The lower cards are specialist readings:

  • Relative. "3 days ago", "in 5 hours". Handy for UI, bad for logs (no anchor).

First the calendars still in official or civic use today:

  • Japanese era. Reiwa since May 2019. Official notation in Japan alongside Gregorian.
  • Chinese. Lunisolar with a 60-year stem-branch cycle. From Chinese New Year on 17 February 2026 the year is 丙午 (bing-wu, "Fire Horse"); the first six weeks of 2026 are still 乙巳 (Wood Snake).
  • Islamic (Hijri). Pure lunar, about 11 days shorter than the solar year. Currently around 1447 AH.
  • Thai Buddhist Era. Thailand's official dating. Same months as Gregorian; the year is 543 higher: 2026 = 2569 BE. Printed on every Thai national ID card and in the Royal Gazette.
  • Indian National (Saka). India's official calendar, introduced 22 March 1957 by the Calendar Reform Committee under Meghnad Saha. The Gazette of India and All India Radio carry it alongside Gregorian. The year starts on 1 Chaitra (22 March, or 21 March in leap years); from that day Saka = Gregorian − 78, and before it − 79.
  • Ethiopian. Civil calendar of Ethiopia, used informally in Eritrea. Twelve 30-day months plus Pagumē of 5 or 6 days. Sits about 7 years 8 months behind Gregorian; New Year (Enkutatash) falls on 11 September (12 September the year before a Gregorian leap year).

Then the historical and specialist notations:

  • Julian Day Number. Continuous day counter since 4713 BC. Astronomers use it because the gap between two JDNs is a simple subtraction - no month boundaries.
  • Mayan Long Count. Five places, baktun.katun.tun.uinal.kin. The famous 13.0.0.0.0 rollover was 21 December 2012. Today (2026) we're at 13.0.13.x.x.
  • French Republican. The revolutionary calendar 1793-1805. Twelve 30-day months plus 5 or 6 sansculottide days at year-end. Surfaces in French history threads.

Y2038 - the 32-bit overflow

On 19 January 2038 at 03:14:07 UTC, a signed 32-bit Unix timestamp hits its maximum value. The next second wraps - many old systems suddenly read 13 December 1901. The converter shows a red warning when your input is past that date.

Who's affected: 32-bit embedded systems, old industrial PLCs, some database schemas with INT(11) for timestamps, older C codebases without time64_t. Who isn't: 64-bit Linux/macOS/Windows, modern JavaScript engines, Postgres / MySQL with BIGINT. The browser itself is 64-bit and renders the value fine.

Building today against dates after 2038 (pensions, insurance, long-term contracts): use 64-bit timestamps or ISO 8601 strings, never 32-bit Unix seconds.

DST marker

Under the input field, the converter shows the next DST transition for the selected timezone. Example: Europe/Berlin switches in 2026 on 25 October (last Sunday) from summer to standard time. Useful for avoiding cron double-runs or meeting collisions.

The European Parliament voted in 2019 to end DST changes. The Council of the EU has not adopted a common position since, so the proposal has stalled. For now the transitions remain.

"Now" button and live mode

Click "Set to now" - the current browser instant loads and the cards animate as they light up, a 1-second self-demo of the tool's full surface. Afterwards the converter runs in live mode: values update each second. As soon as you type in the input field, live mode pauses and you see the typed instant statically.

Timezone selector

By default the converter uses your browser timezone. The dropdown switches to common zones: UTC, Europe/Berlin, Europe/London, America/New_York, Asia/Tokyo, etc. The ISO card then writes the same instant with the offset of the selected zone (+02:00, -07:00, etc.) - switch to UTC and it collapses to …Z.

Important: Unix seconds, Unix milliseconds, Relative, Julian Day, Mayan Long Count, French Republican, stardate, and Discordian are timezone-independent - they count the same absolute instant. Switching the timezone changes the local part of the UTC-and-local card, the offset on the ISO card, and any calendar card whose date can roll over midnight in a different zone (Japanese era, Hijri, Chinese, Thai, Saka, Ethiopian).

FAQ

What is a Unix timestamp and how do I convert it?

A Unix timestamp is the number of seconds since 1 January 1970 00:00:00 UTC. In the converter above, type the value - it auto-detects seconds, milliseconds, microseconds, or nanoseconds.

What's the difference between Unix seconds and milliseconds?

Seconds: 1746576000. Milliseconds: 1746576000000. JavaScript uses ms (Date.now), C/POSIX uses s (time()).

When does a 32-bit Unix timestamp overflow (Y2038)?

19 January 2038 at 03:14:07 UTC. 64-bit systems are unaffected; 32-bit legacy systems flip.

What does today's Mayan Long Count look like?

Today around 13.0.13.x.x. The 13.0.0.0.0 rollover was 21 December 2012.