What is Unix Timestamp Converter?
A Unix timestamp (also called epoch time or POSIX time) is the number of seconds that have elapsed since January 1, 1970 at 00:00:00 UTC, known as the Unix epoch. This universal time representation is used across programming languages, databases, APIs, and operating systems because it is timezone-independent and easy to compare mathematically. This converter lets you instantly translate between Unix timestamps and human-readable date formats. Paste any timestamp (in seconds or milliseconds) and see the corresponding date in ISO 8601, RFC 2822, and locale-specific formats, along with day of week, day of year, ISO week number, and relative time (e.g. 3 days ago). You can also pick a date and time to get the corresponding Unix timestamp. The tool supports 13 major timezones and auto-detects whether your input is in seconds or milliseconds. Everything runs entirely in your browser with zero server calls.
How to Use Unix Timestamp Converter
- 1
Convert a timestamp to a date
Enter a Unix timestamp in the input field (seconds or milliseconds are auto-detected). Click the Now button to fill in the current timestamp. The tool instantly displays the date in ISO 8601, RFC 2822, and locale formats, plus day of week, day of year, week number, and relative time.
- 2
Convert a date to a timestamp
Use the date/time picker in the lower section to select any date and time. The tool immediately shows the corresponding Unix timestamp in both seconds and milliseconds. Click the copy button next to either value to copy it to your clipboard.
- 3
Switch timezones
Select a timezone from the dropdown to see the converted date displayed in that timezone. Choose from UTC, your local timezone, or 11 other major world timezones including US/Eastern, Europe/London, Asia/Karachi, Asia/Tokyo, and more.
Features
- Two-way conversion between Unix timestamps and human-readable dates in real time
- Auto-detection of seconds vs milliseconds input for convenience
- ISO 8601, RFC 2822, and locale-specific date format outputs with copy buttons
- Day of week, day of year, ISO week number, and relative time display
- Live ticking clock showing the current Unix timestamp
- 13 major timezone options including UTC, local, and world cities
- Date/time picker for reverse conversion from any date to Unix timestamp
- Entirely client-side with zero server calls or data collection
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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 (the Unix epoch). It is a universal, timezone-independent way to represent a point in time. Most programming languages, databases, and APIs use Unix timestamps internally for date storage and comparison.
What is the difference between seconds and milliseconds timestamps?+
A seconds-based Unix timestamp is typically 10 digits (e.g. 1700000000), while a milliseconds timestamp is 13 digits (e.g. 1700000000000). JavaScript Date.now() returns milliseconds, while most server-side languages and Unix systems use seconds. This tool auto-detects which format you enter.
What happens after the year 2038?+
The Year 2038 problem affects systems that store Unix timestamps as 32-bit signed integers, which overflow on January 19, 2038. Modern 64-bit systems and JavaScript (which uses 64-bit floats) handle dates far beyond 2038. This tool uses JavaScript Date objects and works correctly for dates well past 2038.
Can I convert negative timestamps?+
Yes. Negative Unix timestamps represent dates before January 1, 1970. For example, -86400 represents December 31, 1969. This tool correctly handles negative timestamps and displays the corresponding pre-epoch date.
Why does my timestamp show a different date than expected?+
The most common reason is a timezone mismatch. Unix timestamps are always in UTC, but the displayed date depends on the selected timezone. Use the timezone selector to switch between UTC and your local timezone. Another reason could be confusing seconds with milliseconds — the tool auto-detects, but verify your input length.
Is my data sent to any server?+
No. All conversions happen entirely in your browser using JavaScript. No timestamps or dates are sent to any server, logged, or stored. You can use this tool offline after the page loads, and it works identically without an internet connection.