Timestamp Converter — Seconds & Milliseconds to Local Date
Convert a 10-digit Unix timestamp in seconds or a 13-digit epoch timestamp in milliseconds to the date and time in your device's timezone. Units are auto-detected and can be set manually, and every result is labelled with its unit and timezone. Convert a date and time back to seconds or milliseconds — all in your browser, with no uploads.
Auto-detected: milliseconds (13 digits)
Milliseconds
Milliseconds
Seconds and milliseconds, both supported
Auto-detect 10-digit seconds or 13-digit milliseconds
Paste either form and the tool picks the right scale: 10 digits are read as Unix seconds, 13 digits as epoch milliseconds.
Manual unit switch when the length is ambiguous
If the number of digits is anything other than 10 or 13, the tool does not guess. It asks you to choose seconds or milliseconds so the result cannot be misread.
Date and time back to seconds or milliseconds
Pick a date and time, then choose whether the timestamp is written in seconds or milliseconds — useful for APIs that expect one specific scale.
Unit and timezone always labelled
Every result states whether it is in seconds or milliseconds and shows the device timezone with its UTC offset, so a converted value is not mistaken for the wrong scale.
Runs locally, nothing uploaded
Conversion uses JavaScript Date inside the browser. Timestamps from private logs or API responses never leave your device.
Frequently asked questions
How does the tool decide between seconds and milliseconds?
A 10-digit timestamp is treated as seconds and a 13-digit timestamp as milliseconds. Any other length is reported as ambiguous and you choose the unit yourself — the tool never silently picks one.
Can I enter a timestamp with a decimal?
Yes. Decimals are accepted and handled to millisecond precision: 1700000000.5 seconds becomes 1700000000500 milliseconds. Anything finer than a millisecond is ignored.
What happens with very large or negative values?
Values outside the range JavaScript dates can represent (roughly ±8.64e15 milliseconds) are rejected with a message. Negative timestamps are supported and convert to dates before 1970.
Which timezone is used?
Your device's local timezone, shown next to the result together with its UTC offset. There is no timezone picker; a Unix timestamp itself is absolute, so the same value shows a different clock time on another machine.
Can I batch-convert or get ISO 8601 / UTC output?
No. The page converts one value at a time and outputs the local date/time string and the numeric timestamp only.
Are my timestamps sent anywhere?
No. Everything runs in the browser and nothing is uploaded.
