Unix Timestamp Converter

One box handles both directions, and the result updates as you type.

1. Look at the Current Unix time banner at the top. It counts up every second, and clicking it drops the current value into the input.
2. Paste a timestamp, or a date such as 2024-05-01 14:30, into the input box.
3. Leave Timestamp unit on Auto detect, or force Seconds or Milliseconds. Auto reads any number of 100,000,000,000 or more as milliseconds, and anything smaller as seconds.
4. Read the Converted block: Local time, UTC, ISO 8601, Unix seconds, Unix millis, Relative, Day of week, Day of year and your time zone with its offset.
5. Read the line under the output, which tells you how the input was interpreted.

The example 1700000000 gives 2023-11-14T22:13:20.000Z and a UTC line of Tue, 14 Nov 2023 22:13:20 GMT. The same instant as 1700000000000 is read as milliseconds and gives an identical result. Everything runs in the page, so values from your logs stay on your device.

Typical uses are reading a created_at column in a database export, checking when a session or cache entry expires, working out what a log line from a server in another zone really says, and producing a timestamp for a test fixture by typing the date you want.

Unix time counts the seconds since 00:00:00 UTC on 1 January 1970 and ignores leap seconds. It is a single integer with no time zone, which is why databases, APIs and JWT claims use it. Turning it into a calendar date means choosing a zone, so one timestamp can fall on different dates in Tokyo and Los Angeles. PHP time() and Python time.time() return seconds, while JavaScript Date.now() and Java return milliseconds, so today a 10-digit value is seconds and a 13-digit value is milliseconds.

• Small millisecond values. Auto detect cannot tell that 86400000 is one day in milliseconds. It reads it as seconds and shows 1972, so switch Timestamp unit to Milliseconds.
• Date-only text. JavaScript reads 2024-05-01 as midnight UTC but 2024-05-01 14:30 as local time, so the two can differ by your zone offset even though the note says local.
• Digit strings. An 8-digit value like 20240501 is a number, not a date, so it is read as seconds in 1970.
• Negative values are accepted and give dates before 1970; fractions of a second are kept.

The UTC line uses the HTTP-date style ending in GMT, as in email and server headers.

A signed 32-bit integer can hold at most 2,147,483,647. As a timestamp that is 03:14:07 UTC on 19 January 2038, and one second later the counter wraps to a negative number that reads as December 1901. Enter 2147483648 and the tool adds a note that it is beyond the 32-bit limit. Modern systems use 64-bit values, but embedded devices, old file formats and some database columns still carry the limit.

• Store times as 64-bit integers or a native timestamp type.
• Keep stored times in UTC and convert only for display.
• Agree whether an API sends seconds or milliseconds, and write it down.
• In JavaScript, new Date(n) wants milliseconds, so multiply seconds by 1000.
• Do not add 86,400 seconds per day across a daylight saving change; use a calendar-aware library.

Related jobs have their own tools. To measure the gap between two dates in days and months, use the date difference calculator. To compare the same moment in several cities, use the time zone converter. To convert a duration between hours, days and weeks, use the time converter, and to read the exp claim of a token, the JWT decoder.

To get the current value in code, use Math.floor(Date.now() / 1000) in JavaScript, time() in PHP, int(time.time()) in Python or date +%s in a Linux shell.