Tools
Timestamp Converter
Convert between Unix timestamps, ISO 8601, and human-readable dates with timezone comparison.
— — — — — ————— — — — | City | Date & Time | Zone |
|---|
About This Tool
Convert between Unix timestamps and human-readable date formats. The tool supports bidirectional sync, automatic detection of seconds vs milliseconds, and comparison across 11 timezones simultaneously.
Features
Bidirectional sync — timestamp and date picker stay synchronized; editing either updates all outputs instantly
Auto-detect seconds / milliseconds — automatically determines the unit based on digit count, with manual override
Multiple output formats — Local time, UTC (ISO 8601), RFC 2822, short date (YYYY-MM-DD), week number, and day of year
Timezone comparison — view the same moment across 11 cities (New York, Los Angeles, Chicago, London, Berlin, Tokyo, Shanghai, Kolkata, Sydney) with your local timezone highlighted
Live clock — current Unix timestamp updates every second with a “Now” button to instantly capture it
Relative time — human-readable “time ago / from now” display that refreshes automatically
Shareable links — timestamps are encoded in the URL (
?ts=…&unit=…) for easy sharingCopy buttons — one-click copy on every output value
How do I use it?
Enter a Unix timestamp to see date, timezone table, and all formats update instantly
Or pick a date and time — the timestamp input and all outputs sync automatically
Click Now to capture the current timestamp
Use the Auto / Seconds / Milliseconds toggle to control unit interpretation (Auto uses digit count heuristic: ≤10 digits → seconds, >10 digits → milliseconds)
Click Share Link to copy a URL that opens the tool with the same timestamp pre-filled
How does auto-detection work?
When the unit selector is set to Auto (default), the tool determines the unit based on the input magnitude:
≤ 9,999,999,999 (10 digits or fewer) → interpreted as seconds. This covers dates up to November 2286.
> 9,999,999,999 (11+ digits) → interpreted as milliseconds. JavaScript’s
Date.now()returns 13-digit millisecond timestamps.
You can always override the auto-detection by selecting Seconds or Milliseconds manually.
Output Formats Reference
Local Time — formatted using your browser’s locale and timezone (
toLocaleString())UTC (ISO 8601) —
2025-01-15T10:30:00.000Z— the standard for APIs, logs, and data interchangeRFC 2822 —
Wed, 15 Jan 2025 11:30:00 +0100— used in email headers and HTTP datesShort Date —
2025-01-15— ISO 8601 date-only formatWeek Number — ISO 8601 week number (W01–W53), useful for sprint planning and reporting
Day of Year — ordinal day (1–366) with total days in the year, useful for Julian date references
Notable Unix Timestamps
| Timestamp | Date (UTC) | Event |
|---|---|---|
0 | 1970-01-01 00:00:00 | Unix Epoch — the origin of Unix time |
1000000000 | 2001-09-09 01:46:40 | One billion seconds since epoch |
1234567890 | 2009-02-13 23:31:30 | Sequential digits — celebrated by developers worldwide |
2000000000 | 2033-05-18 03:33:20 | Two billion seconds since epoch |
2147483647 | 2038-01-19 03:14:07 | Y2K38 — 32-bit signed integer overflow. Systems storing timestamps as |
4294967295 | 2106-02-07 06:28:15 | 32-bit unsigned integer maximum |
Is my data private?
All conversions happen entirely in your browser using JavaScript’s built-in Date and Intl APIs. No timestamp data is transmitted to any server. The shareable link only encodes the timestamp in URL parameters.
Linux Command Reference
Common timestamp operations from the terminal:
How do I get the current timestamp?
How do I convert a timestamp to a date?
How do I convert a date to a timestamp?
How do I convert between timezones?
How do I get a millisecond timestamp?
How do I output ISO 8601 and RFC 2822?
Frequently asked questions
What is a Unix timestamp?
A Unix timestamp is the number of seconds elapsed since the Unix Epoch (1970-01-01 00:00:00 UTC), not counting leap seconds. It is timezone-independent, which makes it ideal for storing and exchanging moments in APIs, logs, and databases.
How do I know if my timestamp is in seconds or milliseconds?
Count the digits: 10 digits or fewer is almost always seconds, while 13 digits (what JavaScript's Date.now() returns) is milliseconds. This tool auto-detects the unit by magnitude, but you can override it with the Seconds / Milliseconds toggle.
Does a Unix timestamp depend on the timezone?
No. The same Unix timestamp represents the same instant everywhere on Earth; only its human-readable rendering changes per timezone. This tool shows that single moment across 11 cities at once so you can compare local times side by side.
What is the Year 2038 problem (Y2K38)?
On systems that store time in a signed 32-bit integer, the timestamp 2147483647 (2038-01-19 03:14:07 UTC) is the maximum value; one second later it overflows to a negative number. The fix is to use 64-bit timestamps, which this tool handles without issue.
Is my data sent to a server?
No. All conversions run entirely in your browser using JavaScript's built-in Date and Intl APIs, and no timestamp data leaves your device. Shareable links only encode the timestamp in URL parameters.