How do millisecond timestamps differ from second timestamps?

A milliseconds timestamp is exactly 1000 times larger than the equivalent seconds timestamp. For example, the seconds timestamp 1700000000 is 1700000000000 in milliseconds.

How do I tell if a timestamp is in seconds or milliseconds?

Timestamps in seconds are around 10 digits long (e.g. 1700000000). Millisecond timestamps are 13 digits long (e.g. 1700000000000). If the value is greater than 9,999,999,999 it is likely in milliseconds.

Where do millisecond timestamps come from?

JavaScript's Date.now() and getTime() return milliseconds since 1 January 1970 UTC, and many JSON APIs and browser logs use the same unit. Paste the 13-digit value to see the date in UTC, ISO 8601 and your local time.

What if I paste a seconds value here?

This page reads the number as milliseconds, so a 10-digit seconds value lands in January 1970. The tool warns when a value is below 10,000,000,000 and suggests a seconds mode.

Millisecond timestamp to date

Enter a Unix timestamp in milliseconds (as returned by JavaScript's Date.now()) to see the equivalent date and time. Also converts to the standard seconds-based timestamp.

Enter a value above to convert

MODE

Runs entirely in your browser

How it works

The number is used as milliseconds directly: 1700000000000 is 2023-11-14T22:13:20.000Z. The Unix (s) row divides by 1000 and rounds down, and the Local row uses your browser's IANA time zone for the offset and daylight saving rules.

Processing runs in your browser

Timestamps are converted entirely in your browser tab. Our servers are not involved at any point.

Related operations

For working out the gap between any two dates, try the date calculator. To find an exact age in years, months, and days, use the age calculator. For aligning timestamps across regions, see the timezone converter.

Frequently asked questions

How do millisecond timestamps differ from second timestamps?: A milliseconds timestamp is exactly 1000 times larger than the equivalent seconds timestamp. For example, the seconds timestamp 1700000000 is 1700000000000 in milliseconds.
How do I tell if a timestamp is in seconds or milliseconds?: Timestamps in seconds are around 10 digits long (e.g. 1700000000). Millisecond timestamps are 13 digits long (e.g. 1700000000000). If the value is greater than 9,999,999,999 it is likely in milliseconds.
Where do millisecond timestamps come from?: JavaScript's Date.now() and getTime() return milliseconds since 1 January 1970 UTC, and many JSON APIs and browser logs use the same unit. Paste the 13-digit value to see the date in UTC, ISO 8601 and your local time.
What if I paste a seconds value here?: This page reads the number as milliseconds, so a 10-digit seconds value lands in January 1970. The tool warns when a value is below 10,000,000,000 and suggests a seconds mode.

Last reviewed September 30, 2026

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