Date / Time → Epoch
Seconds:
Milliseconds:
Epoch → Date / Time
Enter seconds or milliseconds — auto-detected.
UTC:
Local:
ISO 8601:
Current Time
Seconds:
Milliseconds:
UTC:
How It Works
This tool converts between human-readable date/time values and Unix timestamps — entirely inside your browser. No data is sent to a server.
What is a Unix Timestamp?
A Unix timestamp (also called an epoch timestamp) is the number of seconds — or milliseconds — that have elapsed since 00:00:00 UTC on 1 January 1970, known as the Unix epoch. It is a timezone-independent, language-agnostic way to represent a point in time and is widely used in databases, APIs, log files, and JWT tokens.
Implementation Details
All date arithmetic uses JavaScript’s built-in
Date
object — no third-party library is needed.
- Date/Time → Epoch: The
<input type="datetime-local">value is parsed withnew Date(val).Date.getTime()returns the Unix timestamp in milliseconds; dividing by 1000 and flooring gives seconds. The input is pre-filled with the current local time for convenience. - Epoch → Date/Time: The raw number is checked against a threshold of 1010
(approximately November 2286 in seconds). Values above this threshold are treated as
milliseconds; values below are multiplied by 1000 and treated as seconds.
The resulting
Dateobject is then formatted as UTC, local, and ISO 8601 strings using the browser’s native formatting methods. - Live clock: A
setIntervalcallback fires every second, callingnew Date()and updating the current seconds, milliseconds, and UTC string in real time.
Output Formats
| Format | Method | Example |
|---|---|---|
| UTC | Date.toUTCString() | Sat, 01 Jan 2000 00:00:00 GMT |
| Local | Date.toLocaleString() | Depends on browser locale |
| ISO 8601 | Date.toISOString() | 2000-01-01T00:00:00.000Z |
Privacy
All conversions run locally in your browser tab. No timestamps or dates are transmitted anywhere.