How to use the unix timestamp converter
- Choose Timestamp to date or Date to timestamp.
- For a timestamp, paste the number and leave the unit on Detect automatically, or force Seconds or Milliseconds. For a date, enter the date and time and, if needed, the seconds.
- Pick the time zone you want the date shown in, or the zone your date and time belong to. UTC is the default.
- Read the result in Unix seconds, Unix milliseconds, ISO 8601 UTC text and the zone you picked. Use Use the current time if you want the timestamp for right now.
Formula
Seconds = milliseconds / 1,000
UTC moment = 1970-01-01 00:00:00 UTC plus the timestamp in seconds
Timestamp from a local date = UTC moment of that local time, which is local time minus the zone offset on that date
Unix time counts the seconds that have passed since midnight UTC on January 1, 1970, and treats every day as exactly 86,400 seconds. It does not count leap seconds.
Worked examples
Seconds: 1700000000 is Tuesday, November 14, 2023 at 22:13:20 UTC. In New York that moment is 5:13:20 PM, because New York was on standard time (UTC-05:00) that day.
Milliseconds: 1700000000000 has 13 digits, so it is read as milliseconds and gives the same moment.
Date to timestamp: midnight UTC at the start of October 10, 2026 is 1791590400, which is 20,736 days times 86,400 seconds after the start of 1970. The same wall-clock midnight in New York (UTC-04:00 in October) is 14,400 seconds later, 1791604800.
The 32-bit limit: 2147483647 is Tuesday, January 19, 2038 at 03:14:07 UTC, the last second a signed 32-bit integer can hold.
Seconds or milliseconds
Languages and databases disagree about the unit. Many server tools, Unix commands and APIs use seconds. JavaScript, Java and many web APIs use milliseconds. A current timestamp in seconds has 10 digits and in milliseconds has 13.
Automatic detection reads a number below 100 billion as seconds, which covers dates up to November 5138, and a number of 100 billion or more as milliseconds, which covers March 1973 onward. So a millisecond value for a date before March 3, 1973, or a second value for a date after the year 5138, needs the unit set by hand.
Range limits and why they exist
This converter accepts moments from the year 1000 to the year 9999, which is where calendar dates keep four digits. A number outside that range is rejected with a message instead of showing a nonsense date. Dates are shown in the Gregorian calendar, extended backward before 1582.
For zones, the converter uses the rules in your browser. Before about 1970, local clock rules were less uniform and may not match historical records, so use UTC for old dates.
What "current time" means here
The current-time option reads your device clock when the result is calculated. It does not tick, and it is only as accurate as the clock on your device. For exact synchronization, use a system that syncs with a network time source.
Assumptions and limits
- Unix time ignores leap seconds, so each day has exactly 86,400 seconds.
- Supported moments run from the year 1000 to the end of the year 9999 in UTC.
- Seconds may include up to three decimal places. Milliseconds must be whole numbers.
- A date and time in a zone with a skipped hour is rejected. A repeated hour uses the earlier of the two moments and says so.
- The result shows the clock on your device only if you ask for the current time.
Frequently asked questions
What is a Unix timestamp?
It is the number of seconds since 00:00:00 UTC on January 1, 1970, known as the Unix epoch. Computers use it because a single number is easy to store, sort and compare, and it does not depend on a time zone.
How can I tell if a timestamp is in seconds or milliseconds?
Count the digits. Ten digits is almost always seconds for a recent date, and thirteen digits is milliseconds. This tool applies that rule automatically for numbers of 100 billion or more and lets you override it.
Why does my timestamp show a different time than I expected?
The timestamp itself is the same everywhere. The date and clock reading depend on the time zone you view it in, so check that you chose the right zone and remember that daylight saving time shifts the offset.
What happens in the year 2038?
Systems that store Unix time in a signed 32-bit integer run out after 03:14:07 UTC on January 19, 2038. Modern systems use 64-bit values, which this tool also handles up to the year 9999.
Does this tool upload my data?
No. Conversions run in your browser and nothing you enter leaves your device.