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Free Unix Timestamp Converter
A free, private Unix timestamp converter that runs entirely in your browser with zero dependencies. It turns an epoch timestamp into a readable date and turns any date back into a Unix timestamp, both ways, instantly. Paste a value in seconds or milliseconds and the tool auto-detects the unit by digit count, then formats the result with the native JavaScript Intl.DateTimeFormat API in the time zone you pick. The time zone list is built from Intl.supportedValuesOf("timeZone") when your browser exposes it, merged with a small curated fallback list (UTC, your local zone, and common IANA zones) so it still works everywhere. A live clock shows the current Unix time in seconds and milliseconds, ticking once per second. All math is done internally in UTC milliseconds to avoid daylight-saving and locale drift, and every output is one click from your clipboard. Nothing is uploaded, no account is needed, and no value is logged. Because the conversion uses only the platform Date and Intl objects that ship with your browser, it is fast, accurate, and fully offline once the page has loaded.
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Convert epoch time both ways, natively in your browser
This Unix timestamp converter turns an epoch value into a readable date and turns a date back into a Unix timestamp, all inside your browser. There is nothing to install and no account to create: paste a value in seconds or milliseconds, or pick a date and time, and the result appears instantly. The tool auto-detects whether your input is in seconds (10 digits) or milliseconds (13 digits) so you never have to flip a setting.
Under the hood it uses only the standard JavaScript Date object and the Intl.DateTimeFormat API that ship with every modern browser. That zero-dependency approach keeps the page tiny and fast, and it means the conversion is exactly as accurate as the platform you already trust. All math is performed in UTC milliseconds internally, which avoids the daylight-saving and locale drift that catch out naive date handling.
Time zones, a live epoch clock, and honest edge cases
Pick any time zone and the date is formatted with Intl.DateTimeFormat for that zone. The selector is populated from Intl.supportedValuesOf("timeZone") when your browser supports it, which exposes the full set of IANA zones like America/New_York, Europe/London, and Asia/Tokyo. On older browsers it falls back to a curated list that always includes UTC and your own local zone, so the tool stays useful everywhere.
A live clock at the top shows the current Unix time in both seconds and milliseconds, updating once per second, so you can grab "now" without leaving the page. The converter also handles the awkward cases honestly: negative timestamps for dates before 1970 convert correctly, and values beyond the JavaScript Date range (about 271,821 BC to 275,760 AD) are clearly flagged as out of range instead of silently producing a wrong date.
Private by design: nothing leaves your browser
Unlike converters that round-trip your data through a server, this tool does every calculation locally with the browser native Date and Intl APIs. The timestamps and dates you enter are never uploaded, stored remotely, or logged, and there is no analytics call in the conversion path. You can verify this at any time by opening the Network tab in your browser DevTools while converting and confirming that no request carries your input.
Because the logic runs entirely on your device, the tool also works offline once the page has loaded, which is ideal when you are debugging logs on a locked-down machine or working without a stable connection. Every output, from the ISO 8601 string to the localized date to the raw epoch value, is one click from your clipboard.
How It Works
Type or paste a Unix timestamp in seconds or milliseconds, or pick a date and time: the tool auto-detects the unit by digit count.
Choose a time zone from the list (built from your browser Intl data) and the date is formatted with the native Intl.DateTimeFormat API.
Read the converted result in both directions, watch the live current-epoch clock, and copy any value to your clipboard with one click.
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Key Features
Privacy & Trust
Use Cases
Limitations
- Time zone names depend on your browser: very old browsers without Intl.supportedValuesOf fall back to a smaller curated list rather than the full IANA database
- Daylight-saving transitions and historical zone offset changes are only as accurate as the time zone data shipped in your browser engine
- The JavaScript Date type is limited to roughly plus or minus 8.64e15 milliseconds (about 271,821 BC to 275,760 AD); values outside that range are flagged as out of range
- Sub-second precision is limited to milliseconds: microsecond or nanosecond timestamps must be reduced to milliseconds first
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Frequently Asked Questions
Is this Unix timestamp converter free?
Yes, it is completely free with no limits. You can convert as many timestamps and dates as you like, in either direction and across any time zone, without paying, signing up, or installing anything. It is a single web page that uses only the standard JavaScript Date and Intl features already built into your browser.
Is my data sent to a server?
No. Every conversion runs locally in your browser using the native Date and Intl.DateTimeFormat APIs. The timestamps and dates you enter are never uploaded, stored remotely, or logged. You can confirm this yourself by opening the Network tab in your browser DevTools while converting: you will see no request that carries your input.
What is a Unix timestamp and what is epoch time?
A Unix timestamp, also called epoch time or POSIX time, is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970, not counting leap seconds. Many systems use the millisecond variant (seconds times 1000), which is what JavaScript Date.now() returns. This tool reads both and tells you which unit it detected.
How does it tell seconds apart from milliseconds?
It auto-detects the unit by the number of digits. A 10-digit value is treated as seconds and a 13-digit value as milliseconds, which covers all realistic dates around the current era. The detected unit is shown next to the result, and the tool computes everything internally in UTC milliseconds so the two stay consistent.
Do I need to install anything, and does it work offline?
No installation is needed: it is just a web page. The conversion logic runs entirely on your device with no dependencies, so once the page has loaded it works offline. You only need a connection for the initial page load; after that you can convert timestamps with no further network access.
Which time zones can I convert to?
The selector is populated from your browser via Intl.supportedValuesOf("timeZone"), which in modern browsers lists the full set of IANA time zones such as America/New_York, Europe/London, and Asia/Tokyo. On older browsers that lack this API, the tool falls back to a curated list that always includes UTC and your own local time zone, so a useful set of zones is available everywhere.
Can it handle dates before 1970 or very large timestamps?
Yes for dates before 1970: a negative Unix timestamp represents an instant earlier than the epoch, and the tool converts it correctly. For very large values there is a hard limit from the JavaScript Date type, which spans roughly plus or minus 8.64e15 milliseconds (about the years 271,821 BC to 275,760 AD). Anything outside that range is flagged as out of range rather than producing a wrong date.