Time / Unix Timestamp Converter
This tool converts a Unix timestamp into a readable date and time and back from a date to a timestamp. It handles both second- and millisecond-based stamps, shows the result in your device's local time, and displays the current Unix timestamp live. Ideal for developers, testers and anyone working with logs, APIs or databases. Everything runs directly in your browser.
Current timestamp: – s
How time conversion works
A Unix timestamp (also called Unix time or POSIX time) is a single number expressing the count of seconds elapsed since 1 January 1970 00:00:00 UTC — this moment is known as the "epoch". For example, the value 1700000000 corresponds to 14 November 2023. The higher the number, the later the moment; times before 1970 are written as negative numbers.
The tool recognises two notation ranges. If the entered number has fewer than 13 digits, it treats it as seconds and multiplies it by a thousand for conversion (JavaScript works internally in milliseconds). A number with 13 or more digits is treated as milliseconds. The resulting date is then shown in your local time according to your device settings, not in UTC — which is why the same timestamp shows a different clock time to someone in Prague and in New York.
The reverse direction works symmetrically: from the date-and-time field (datetime-local) the tool calculates the matching timestamp in both seconds and milliseconds. The input is therefore either a number or a calendar date; the output is always the other format.
How to use time conversion
- Enter a number into the Unix timestamp field (e.g.
1700000000). The matching date and time in your time zone appears instantly below. - For the opposite direction, click the Date and time field and pick a specific moment. The tool computes the timestamp in both seconds and milliseconds.
- The Current timestamp value at the bottom ticks in real time — handy when you need "now" as a number.
| Input | Type | Result (local time) |
|---|---|---|
| 1700000000 | seconds | 14 Nov 2023, 23:13:20 |
| 1700000000000 | milliseconds | 14 Nov 2023, 23:13:20 |
| 0 | seconds | 1 Jan 1970, 01:00:00 (CET) |
What time conversion is good for
The Unix timestamp is the most common way computers store time — you'll find it in databases, API responses, server logs, JWT tokens and file metadata. When you're debugging an app and see a bare number in a log, this tool translates it into a human-readable moment in a second. Conversely, when testing and you need a specific timestamp as input, you can easily generate it from a date.
Common uses: checking token validity, comparing two events in a log, preparing test data, or quickly finding "what's the Unix time now". Because the entire conversion runs locally in your browser, no entered date or timestamp ever leaves your device — so you can safely work even with data from internal systems.
FAQ
What is a Unix timestamp?
It is the number of seconds since 1 January 1970 00:00:00 UTC (the epoch). It's a simple numeric way for computers to store and compare time independently of time zone and format.
How does the tool tell whether a number is in seconds or milliseconds?
By digit count. If the input has fewer than 13 digits it treats it as seconds and multiplies by a thousand; 13 or more digits is treated as milliseconds. Today's second stamps have 10 digits, millisecond stamps 13.
Which time zone is the result shown in?
In your local time according to your device settings (via the browser's toLocaleString function). A Unix timestamp itself carries no zone — it always refers to a moment in UTC, which the tool recalculates to your local clock.
Why does timestamp 0 show 1:00, when I expect midnight?
Timestamp 0 is midnight on 1 Jan 1970 in UTC. In Central Europe (CET, UTC+1) that corresponds to 01:00 local time. The difference is exactly your time zone's offset from UTC.
Does the tool support dates before 1970?
The timestamp field treats entries as non-negative numbers, so it won't process negative (pre-epoch) values there. However, via the Date and time field you can pick an earlier date and the tool will compute the matching (negative) timestamp.
Is the entered date sent to a server?
No. The entire conversion runs solely in your browser using JavaScript. No timestamp or date leaves your device, and no connection or registration is required.
What is the Year 2038 problem?
Systems that store Unix time as a signed 32-bit integer overflow on 19 January 2038. Modern environments including JavaScript use a larger range, so they are not affected.
Does the tool handle millisecond precision?
Yes. When you enter a date it computes the stamp in both seconds and milliseconds, and it correctly recognises millisecond input timestamps (13+ digits) and converts them to a date.
Sources & standards
📅 Last updated: 16 July 2026