What is epoch in milliseconds?

It is the number of milliseconds since 1 January 1970 UTC. JavaScript's Date.now() returns this value, which is 1000 times larger than the more common epoch-in-seconds.

Can it convert a date back to epoch milliseconds?

Yes. Switch to "Date to epoch ms" and enter any date the browser can parse, such as an ISO 8601 string, to get both milliseconds and seconds.

Yes. Conversion uses the browser's built-in Date object locally — no network calls are made and nothing is stored.

What is the difference between epoch milliseconds and epoch seconds?

Both count from 1 January 1970 UTC. Seconds is the classic Unix timestamp; milliseconds is that value times 1000 and is what JavaScript uses. A 13-digit number is almost always milliseconds and a 10-digit number is seconds.

How do I convert epoch milliseconds to seconds?

Divide by 1000 (and usually drop the fractional part). For example 1700000000000 ms ÷ 1000 = 1700000000 seconds. This tool shows both values side by side automatically.

Which date formats can I paste in?

Anything the browser's Date parser accepts — most commonly an ISO 8601 string like 2026-05-30T12:00:00Z, but also many human-readable forms. ISO 8601 with a timezone is the most reliable.

Why does the local time differ from the UTC time shown?

Epoch values are absolute moments in UTC. The tool also renders that instant in your device's local timezone, so the two displays differ by your UTC offset — they refer to the same instant.

What is the Epoch Milliseconds Converter?

Convert epoch time in milliseconds to a readable date, or turn any date back into epoch milliseconds and seconds. Two-way, copy-ready, and fully client-side — nothing is uploaded. It runs free in your browser on Gera Tools, with nothing uploaded.

Epoch Milliseconds Converter

Name: Epoch Milliseconds Converter
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

Epoch milliseconds converter

A timestamp in your logs or database is often a bare number like 1700000000000. That’s epoch milliseconds — the count of milliseconds since 1 January 1970 UTC, the format JavaScript’s Date.now() returns. This converter turns that number into a readable date and back again, both directions, with copy buttons for each format.

How it works

The tool uses the browser’s native Date object — no rounding tricks or external libraries. In Epoch ms to date mode it constructs a date from your millisecond value and renders it as an ISO 8601 string, a UTC time and your local time. In Date to epoch ms mode it parses any date the browser understands and reports getTime() (milliseconds) plus that value divided by 1000 (the classic Unix seconds). A 13-digit input is milliseconds; a 10-digit input is seconds.

Example

Paste 1700000000000:

Output	Value
ISO 8601 (UTC)	2023-11-14T22:13:20.000Z
Epoch seconds	1700000000
Epoch milliseconds	1700000000000

Switch direction and type 2023-11-14T22:13:20Z to get 1700000000000 back. Every output has a copy button, so you can grab exactly the format your code or database expects. The conversion runs entirely on your device.

Epoch ms versus epoch seconds: when each appears

Epoch seconds (a 10-digit number) is the classic Unix timestamp, used by Unix file mtimes, POSIX system calls, most SQL TIMESTAMP columns, Python’s time.time(), and many C and Go APIs. Divide epoch milliseconds by 1000 to get epoch seconds.

Epoch milliseconds (a 13-digit number) is what JavaScript uses natively — Date.now(), new Date().getTime(), and most Node.js timer APIs return this. Browser performance APIs and many REST API responses in JSON also default to milliseconds.

Epoch microseconds (a 16-digit number) and nanoseconds (19 digits) appear in high-precision systems — database write-ahead logs, distributed tracing, kernel timestamps. They are rarer in application code but recognisable by digit count.

Spotting the format from digit count

Digit count	Likely format	Approximate era
10	Epoch seconds	2001 – 2286
13	Epoch milliseconds	2001 – 2286
16	Epoch microseconds	2001 – 2286
19	Epoch nanoseconds	2001 – 2286

A 10-digit number starting with 1 is almost certainly a Unix timestamp in the 2001–2033 window. A 13-digit number starting with 1 is the same moment expressed in milliseconds. If you see an 11 or 12-digit number you likely have a truncated timestamp or an unusual encoding — paste it here to see what date it decodes to and sanity-check the result.

Common debugging use cases

Log correlation: server logs and browser devtools both emit epoch timestamps, but servers often log in seconds while JS clients log in milliseconds. Paste both here to confirm they represent the same moment.

Token expiry debugging: JWT exp and iat claims use epoch seconds. Convert them to readable dates to verify a token has not expired or been issued in the future.

Database timestamp inspection: PostgreSQL EXTRACT(EPOCH FROM now()) returns seconds as a float; MongoDB ObjectIDs embed epoch seconds in the first 4 bytes. Convert to human-readable form to verify data consistency.