CHECK EPOCH VALUES AND TIMEZONES
Make a timestamp readable in any timezone.
Convert Unix timestamps in seconds or milliseconds to a date in a chosen timezone, or convert a timezone-explicit ISO 8601 date back to a timestamp.
Choose seconds or milliseconds explicitly. ISO input must include Z or a numeric offset.
Choose an input type and enter a value to convert.
Conversion method and limits
A Unix timestamp identifies an instant as a count from 1970-01-01 00:00:00 UTC. JavaScript Date uses milliseconds, so seconds are multiplied by 1,000 before formatting. The selected timezone affects the displayed local date and clock only; the UTC instant and timestamp stay the same. This tool uses the browser's Date and Intl timezone data and does not fetch a time service.
Seconds and milliseconds are explicit choices because their digit counts are only a clue, not a safe way to infer a unit. ISO input must include a UTC marker (Z) or numeric offset. The converter rejects malformed values and dates outside the JavaScript Date range.
Example: 0 seconds and 0 milliseconds both identify 1970-01-01T00:00:00.000Z. In Asia/Shanghai that same instant displays as 1970-01-01 08:00:00 (UTC+08:00).
Page content updated November 3, 2026.
Runs in your browser. No uploads. No account.
Good to know
Why are seconds and milliseconds separate choices?
JavaScript Date timestamps use milliseconds, while many Unix timestamp values are expressed in seconds. Selecting the unit avoids silently converting a value with the wrong scale.
How much timestamp precision does this keep?
JavaScript Date stores an integer number of milliseconds. Finer fractions are discarded: for example, 1.234567 seconds converts to 1,234 milliseconds, or 1.234 seconds. ISO input accepts up to three fractional-second digits.
Does changing the timezone change the Unix timestamp?
No. A timestamp is one instant. Timezones display that instant with different wall-clock dates and offsets, including daylight-saving changes where applicable.
Why must ISO input include a timezone?
A date and clock without a timezone can mean different instants on different devices. This tool requires Z or a numeric UTC offset and rejects timezone-free date-times.
Why might another device show a different local time?
Timezone rules can change and browser timezone databases can differ in age. The tool relies on the timezone data installed in the browser.
Does my value leave the browser?
No. Parsing and formatting happen locally in this browser tab; the tool does not upload or store your input.
Is it free?
Yes, during beta. Optional usage-credit plans are coming soon. Payments are not available and no credits are required.
Source
Method checked November 3, 2026. MDN documents that JavaScript Date stores an integral millisecond timestamp since the UTC epoch and that timezone interpretation affects display.
How it works
1. Choose whether the input is a Unix timestamp in seconds, milliseconds, or an ISO 8601 date with an explicit timezone. 2. Enter the value and choose a display timezone. 3. Read the converted timestamp, UTC instant, and timezone-formatted date.
Good to know
How can I tell seconds from milliseconds?
Unix timestamps in seconds are usually about ten digits today; milliseconds are usually about thirteen. This tool never guesses: choose the unit that matches your input.
Does the timezone change the timestamp?
No. A timestamp identifies one instant. The timezone changes only the human-readable clock and date shown for that instant.
Which ISO 8601 inputs are accepted?
Use a full date and time such as 2026-11-03T09:30:00Z or 2026-11-03T09:30:00+08:00. An explicit Z or numeric UTC offset is required so the instant is unambiguous.
Where does timezone data come from?
Date parsing and timezone formatting use the browser's built-in JavaScript Date and Intl APIs. Results can depend on the browser's installed timezone data.
Does the tool send my value anywhere?
No. Conversion runs in this browser tab. The tool does not upload or save the input.
Is it free?
Yes, during beta. Optional usage-credit plans are coming soon. Payments are not available and no credits are required.