Milliseconds to Date Converter

About the Milliseconds to Date Converter

The milliseconds to date converter turns a Unix timestamp into a human readable date and time. It also works in reverse and turns a date into a timestamp.

The bar at the top shows the current Unix time in milliseconds, updating live. The Timestamp to date tab accepts milliseconds or seconds and detects which one you entered. It returns the date in your local time, the date in UTC, the ISO 8601 format, the value in seconds and milliseconds, and how long ago or how far ahead that moment is. The “Use current time” button fills in the timestamp for right now.

The Date to timestamp tab takes a date and time, read as your local time or as UTC, and returns the timestamp in milliseconds and seconds.

How to Use the Milliseconds to Date Converter

1. Paste a timestamp into the box, or press “Use current time”.
2. Read the local date, UTC date and ISO 8601 value.
3. To go the other way, open “Date to timestamp”, pick a date and time, and choose local time or UTC.

What Is a Unix Timestamp?

A Unix timestamp, also called epoch time, is the number of seconds that have passed since 00:00:00 UTC on Thursday, January 1, 1970. That starting point is called the Unix epoch. A timestamp of 0 is the epoch itself, and 86,400 is one day later.

Unix time always counts from UTC, so the same number means the same moment everywhere. It ignores leap seconds, so every Unix day is exactly 86,400 seconds.

Milliseconds or Seconds?

• 10 digits, such as 1700000000, is seconds.
• 13 digits, such as 1700000000000, is milliseconds for the same moment (November 14, 2023).
• 16 digits is microseconds and 19 digits is nanoseconds.

The converter reads any value of 100 billion or more as milliseconds and smaller values as seconds. The result tells you which reading it used.

How to Convert Milliseconds to a Date

1. Divide milliseconds by 1,000 to get seconds.
2. Divide seconds by 86,400 to get whole days since January 1, 1970.
3. Count that many days forward on the calendar, allowing for leap years.
4. The remaining seconds give the time of day in UTC.
5. Add or subtract your UTC offset for local time.

Unix Time in Programming Languages

• JavaScript: Date.now() returns milliseconds. new Date(ms) builds a date.
• Python: time.time() returns seconds.
• PHP: time() returns seconds.
• Java: System.currentTimeMillis() returns milliseconds.
• MySQL: UNIX_TIMESTAMP() returns seconds and FROM_UNIXTIME() converts back.
• Linux and macOS: date +%s prints seconds.
• Excel and Google Sheets: =A1/86400000+DATE(1970,1,1) converts milliseconds in A1 to a UTC date.

Notable Unix Timestamps

The Year 2038 Problem

Older systems store Unix time as a signed 32 bit integer. Its largest value, 2,147,483,647, is reached at 03:14:07 UTC on January 19, 2038. One second later, the counter overflows to a negative number, which those systems read as a date in December 1901. Modern systems use 64 bit time, which will not overflow for about 292 billion years.

ISO 8601 Format

ISO 8601 is the international date and time format, such as 2023-11-14T22:13:20.000Z. It sorts correctly as text and includes the time zone. The final Z means UTC, also called Zulu time.

Frequently Asked Questions