--- title: "Unix Timestamp Converter" description: "Convert Unix timestamps to human-readable dates and vice versa. Supports seconds and milliseconds. An epoch converter for developers, in your browser." url: https://findutils.com/developers/unix-timestamp/ category: developers --- # Unix Timestamp Converter Convert Unix timestamps to human-readable dates and vice versa. Supports seconds and milliseconds. An epoch converter for developers, in your browser. **Use this tool:** [Unix Timestamp Converter](https://findutils.com/developers/unix-timestamp/) ## Programmatic access - REST id `unix-timestamp-convert`: POST https://api.findutils.com/api/tools/unix-timestamp-convert/execute (reference: https://findutils.com/api/unix-timestamp-convert/) - MCP tool `unix_timestamp_convert` on https://mcp.findutils.com (reference: https://findutils.com/mcp/unix-timestamp-convert/) ## What is a Unix Timestamp? A Unix timestamp (also known as Epoch time or POSIX time) is the number of seconds that have elapsed since January 1, 1970, at 00:00:00 UTC. This moment is called the Unix Epoch. Because Unix time is a single integer independent of time zones, daylight saving rules, and calendar quirks, it has become the standard way to record and exchange points in time across operating systems, programming languages, databases, and web APIs. ## Tips for Working with Unix Timestamps - A 10-digit number is in seconds; a 13-digit number is in milliseconds. Dividing a millisecond timestamp by 1000 gives you the seconds equivalent. - Negative timestamps represent dates before January 1, 1970. For example, -86400 equals December 31, 1969. - JavaScript Date.now() returns milliseconds, while Python time.time() returns seconds with decimal precision. Know which format your language uses before comparing values. - Always store timestamps in UTC. Convert to local time only at the presentation layer to avoid off-by-one-hour bugs from daylight saving transitions. - The Year 2038 problem affects 32-bit signed integers that overflow on January 19, 2038. Use 64-bit timestamps in modern systems to avoid this limit. ## Frequently Asked Questions ### What is a Unix timestamp? A Unix timestamp is the number of seconds that have elapsed since January 1, 1970, at 00:00:00 UTC. This reference point is called the Unix Epoch. The format is used universally in software, databases, and APIs because it is timezone-independent and easy to compare mathematically. ### How do I convert a Unix timestamp to a readable date? Paste the timestamp into the converter input field. The tool instantly displays the corresponding date and time in UTC, your local timezone, and ISO 8601 format. It works with both 10-digit second values and 13-digit millisecond values. ### What is the difference between seconds and milliseconds timestamps? A standard Unix timestamp is a 10-digit integer counting seconds since the Epoch. A millisecond timestamp is a 13-digit integer that includes three extra digits for sub-second precision. JavaScript uses milliseconds by default, while most server-side languages use seconds. This converter detects the format automatically. ### What is the Year 2038 problem? Systems that store Unix time in a 32-bit signed integer will overflow on January 19, 2038, at 03:14:07 UTC. The maximum value a 32-bit signed integer can hold is 2,147,483,647, which corresponds to that exact moment. Modern 64-bit systems use larger integers that will not overflow for billions of years. ### Can I convert a calendar date to a Unix timestamp? Yes. Switch to the Date to Timestamp tab, select a date and time using the picker, and the tool outputs the corresponding Unix timestamp in both seconds and milliseconds. This is useful when constructing API query parameters or database filters. ### Are negative Unix timestamps valid? Yes. A negative value represents a date before the Unix Epoch. For example, -86400 corresponds to December 31, 1969, exactly one day before the Epoch. Most modern systems and this converter handle negative timestamps correctly. ### Does the converter require a signup, and is it safe to use? No signup. It is available with no account and no usage limits. All conversions happen in your browser using JavaScript. No data is sent to any server, so your timestamps remain private. ### How do different programming languages handle Unix timestamps? Python's time.time() returns seconds as a float. JavaScript's Date.now() returns milliseconds as an integer. PHP's time() returns seconds. Java's System.currentTimeMillis() returns milliseconds. Always check whether your language uses seconds or milliseconds to avoid off-by-a-factor-of-1000 bugs. ### What is the maximum Unix timestamp? On 32-bit systems the maximum is 2,147,483,647 (January 19, 2038). On 64-bit systems the practical limit is 9,223,372,036,854,775,807, which represents a date roughly 292 billion years in the future, far beyond any foreseeable need. ### What is the Unix Epoch and why was it chosen? The Unix Epoch is January 1, 1970, 00:00:00 UTC. It was chosen by the early Unix developers at Bell Labs as a conveniently recent, round date. 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