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.

Epoch Milliseconds Converter

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.