Unix Timestamp Converter

How to use the Unix Timestamp Converter

1. The top box shows the current Unix time in seconds and milliseconds, updating live. Click Copy to grab it.
2. Choose the time zone you care about. It is used for both conversions; your browser's zone is selected by default.
3. To read a timestamp, paste it into Timestamp → date. The unit is detected from its size, or you can pick seconds, milliseconds, microseconds or nanoseconds.
4. Read the result in UTC, your local time, the chosen zone, ISO 8601, RFC 2822 and as a relative time like "3 days ago".
5. To get a timestamp, type a date in Date → timestamp as YYYY-MM-DD HH:MM:SS. It is read as a time in the chosen zone unless you add Z or an offset.

How it works

A Unix timestamp counts the seconds since the "epoch", 00:00:00 UTC on January 1, 1970, ignoring leap seconds. It is the same number everywhere in the world at a given moment, which is why computers use it. Times before 1970 are negative: -86400 is December 31, 1969. Many systems, including JavaScript, count milliseconds instead, giving 13-digit values today, and some databases and tracing tools use microseconds or nanoseconds.

Auto-detection looks at the size of the number. Values under 100 billion are read as seconds (that covers the years from about 1200 to 5100), up to 100 trillion as milliseconds, then microseconds, then nanoseconds. Large inputs are handled as exact integers, so a nanosecond timestamp is not rounded before it is converted. The tool can show any date that JavaScript dates support, roughly 273,000 years either side of 1970. RFC 2822 (the email date format) is only shown for years 1900–9999, which is all that standard allows.

Turning a calendar date into a timestamp needs a time zone, because 9:00 in Denver and 9:00 in London are different moments. The tool uses your browser's built-in time zone database to find the UTC offset in effect on that date, including daylight saving time. Example: 2026-07-04 12:00:00 in America/Denver (UTC−6 in summer) is 2026-07-04T18:00:00Z, which is 1783188000. When clocks spring forward, some local times never happen; when they fall back, some happen twice. The tool tells you when that applies and which moment it picked.

UNIX is a registered trademark of The Open Group. "Unix time" is used here only in its common technical sense.

Frequently asked questions

How do I know if my timestamp is in seconds or milliseconds?
Count the digits. Present-day timestamps in seconds have 10 digits (like 1759500000); in milliseconds they have 13. Auto mode does this for you, and you can override it with the unit buttons.

What is the year 2038 problem?
Older systems store Unix time in a signed 32-bit integer, which runs out at 2147483647, or 03:14:07 UTC on January 19, 2038. After that it wraps to a negative number and jumps back to 1901. Modern systems use 64-bit values, which last far beyond any practical date.

Does Unix time include leap seconds?
No. Every day counts as exactly 86,400 seconds. When a leap second happens, Unix time effectively repeats or stretches a second, so you can't use it to count real elapsed seconds across a leap second.

Why is my local time different from what a colleague sees?
The timestamp is the same; only the display differs. Pick a time zone from the list to see the time anywhere, or compare the UTC line, which is the same for everyone.

Can I enter dates before year 1 or after 9999?
Yes. Type negative years like -0500-06-01 (year −500 in astronomical numbering, which is 501 BC) or years with more digits. ISO 8601 shows such years with a sign and six digits, as the standard requires.