Date to Unix Timestamp – Date and Time to Epoch Converter

A Unix timestamp is Unix time written as a single number: the count of seconds since the start of 1970 in UTC[1]. Midnight on January 1, 1970 has the timestamp 0, and the timestamp goes up by one with every second after that.

POSIX, the shared standard for Unix-like systems, gives the formula for the timestamp of a date. The formula adds up the seconds, the minutes times 60, the hours times 3,600 and the days times 86,400, with a correction for leap years[2]. Every day in this calculation has exactly 86,400 seconds.

A date written for people always assumes some time zone, while the timestamp itself holds no time zone information[3]. That is why 10:00 AM on a clock in New York and 10:00 AM on a clock in London give two different timestamps.

Midnight UTC on January 1, 2025 is the Unix timestamp 1735689600. Midnight on the same day in New York came five hours later, because Eastern Standard Time is five hours behind UTC[4]. Its timestamp is 1735707600.

To get the timestamp of any date, enter it in the Date and time field, for example 2025-01-01 00:00:00 or 2025/01/01 00:00. The result in seconds appears in the Unix Timestamp field. Below it, the converter gives the same moment in milliseconds, the unit in which Date.now() returns the time in JavaScript[5].

The converter reads a date without a zone as UTC. If you enter a time from a clock in New York or London, choose Local time in the Time zone switch. The converter then reads the time in your device's time zone, with daylight saving time taken into account.

A date with an offset added, such as 2025-01-01T00:00:00-05:00, is read with that offset under both options.

Copy the result with the Copy result button.

The timestamp is the number of full days since January 1, 1970, multiplied by 86,400, plus the seconds that have passed since midnight on that day[2].

Take November 14, 2023, at 22:13:20 UTC. From January 1, 1970 to that day, 19,675 full days passed. Multiplying by 86,400 gives 1699920000 seconds.

The time 22:13:20 is 80,000 seconds after midnight. Adding the two numbers gives the timestamp 1700000000.

Convert a date written in New York time to UTC first. In winter you add five hours, or 18,000 seconds. During daylight saving time you add four hours, or 14,400 seconds[4]. Midnight on January 1, 2025 in New York is therefore 1735689600 plus 18,000, which is 1735707600. For a time during British Summer Time in the UK, you subtract 3,600 seconds[6].

The Unix timestamp to date converter turns the result back into a date. If a system expects the timestamp in hexadecimal, convert the result in the decimal to hex converter. The timestamp 1700000000 is 6553F100 in hexadecimal.

On the first Sunday of November, daylight saving time in the US ends at 2:00 AM[7], and clocks go back to 1:00 AM standard time. Every time from 1:00 to 1:59 AM then happens twice, so each of those times matches two timestamps.

In that case the converter, with the Local time option, picks the earlier of the two moments, as the JavaScript Date object does[15]. To get the second moment, one hour later, add the offset to the date. The entry 2026-11-01 01:30:00 -05:00 gives the timestamp 1793514600. On a device set to New York time, you can see both moments as local times when you paste these timestamps into the Unix timestamp to date converter and choose Local time.

On the second Sunday of March, daylight saving time begins at 2:00 AM[7], and clocks jump straight to 3:00 AM. The time 2:30 AM does not appear on US clocks that day. The converter moves such an entry one hour forward, as Date does[15], and gives the timestamp for 3:30 AM daylight saving time.

In the UK, clocks go forward at 1 AM on the last Sunday of March and back at 2 AM on the last Sunday of October[6], so London has the same two situations on those days. With the UTC option, every time you enter has exactly one timestamp, because UTC does not switch to daylight saving time.