Convert epoch timestamps to dates and back — free, fast, private.
What is a Unix timestamp?
A Unix timestamp (also called epoch time or POSIX time) is the number of seconds that have
elapsed since 1 January 1970, 00:00:00 UTC — the "Unix epoch". Leap seconds are not counted, so
every day is treated as exactly 86,400 seconds. Because a timestamp is a single number, it is the
standard way computers store, compare and transmit points in time. Some systems use milliseconds
(thousandths of a second) instead of seconds for extra precision — this tool detects and converts
both automatically.
How to use this tool
- The first panel always shows the current Unix time, ticking live in seconds and milliseconds.
- Paste any timestamp into the timestamp field — seconds or milliseconds are detected automatically — and instantly see the date in UTC, your local time, ISO 8601 format and relative time (for example "3 days ago").
- To go the other way, pick a date and time in the last panel to get the matching timestamp in seconds and milliseconds.
- Click any Copy button to copy a result to your clipboard.
Common epoch milestones
- 0 — 1970-01-01 00:00:00 UTC, the Unix epoch itself.
- 1000000000 — 2001-09-09 01:46:40 UTC, the first "billennium".
- 1234567890 — 2009-02-13 23:31:30 UTC, a famous palindrome-like milestone.
- 1767225600 — 2026-01-01 00:00:00 UTC.
- 2147483647 — 2038-01-19 03:14:07 UTC, the largest value a signed 32-bit integer can hold (see the Year 2038 problem in the FAQ).
Popular timestamps
Well-known epoch milestones and the upcoming New-Year boundaries, each with its own page:
Common mistake: mixing up seconds and milliseconds
The single most frequent timestamp bug is a unit mismatch. JavaScript's Date.now() returns milliseconds, while most server-side languages and APIs return seconds. Pass 1767225600000 where seconds are expected and the resulting date lands roughly 56,000 years in the future; pass 1767225600 where milliseconds are expected and you get 1970-01-21 10:53:45 UTC. The fix: after pasting a value above, read the status line under the timestamp field. This tool prints "Detected seconds" or "Detected milliseconds" on every conversion, so you always know which unit your number was interpreted as before you trust the result.
Which unit does your language use?
| Language | Function | Unit returned |
|---|
| JavaScript | Date.now() | Milliseconds |
| Python | time.time() | Seconds (float) |
| Java | System.currentTimeMillis() | Milliseconds |
| Go | time.Now().Unix() | Seconds |
| PHP | time() | Seconds |
| Unix shell | date +%s | Seconds |
Pro tip: dates before 1970
The timestamp field also accepts negative values, which represent moments before the Unix epoch. For example, -1 converts to 1969-12-31 23:59:59 UTC and -86400 is 1969-12-31 00:00:00 UTC. Useful when working with historical records or testing boundary conditions in date-handling code.
Frequently asked questions
What is a Unix timestamp?
A Unix timestamp is the number of seconds elapsed since the Unix epoch — 1 January 1970, 00:00:00 UTC — not counting leap seconds. It is timezone-independent: the same number describes the same instant everywhere on Earth, which is why computers use it to store and exchange time.
What is the Year 2038 problem?
Many older systems store timestamps as a signed 32-bit integer, which overflows at 2147483647 — 2038-01-19 03:14:07 UTC. One second later the value wraps to a negative number, which those systems would read as 1901. Modern 64-bit systems are unaffected, but embedded and legacy software must be updated before 2038.
How do I know if my timestamp is in seconds or milliseconds?
Look at the number of digits. A current timestamp in seconds has 10 digits (around 1.7 billion), while the same instant in milliseconds has 13 digits (around 1.7 trillion). This tool detects the unit automatically: any value of 12 digits or more is treated as milliseconds.
Which timezone does the epoch use?
UTC. The epoch is defined as 1970-01-01 00:00:00 UTC, and timestamps count seconds from that moment with no timezone or daylight-saving offset applied. Timezones only matter when a timestamp is displayed as a human-readable local date and time.