Unix Timestamp Converter
Convert Unix timestamps to dates and back — free, instant, and entirely private.
Current time
How it works
A Unix timestamp counts seconds (or, in JavaScript's convention, milliseconds) since midnight UTC on January 1, 1970. This tool detects which unit you entered by digit count, converts it to a JavaScript Date, and shows it back as an ISO 8601 string, a UTC string, and your browser's local time — all computed instantly with the browser's built-in Date object, with nothing sent anywhere.
The "current time" panel at the top updates every second so you can grab a live timestamp for testing or debugging without doing the math yourself. The second converter runs in reverse: paste any date your browser can parse (ISO 8601 is the most reliable format) and get back its Unix timestamp in seconds.
Useful for reading timestamps out of logs, API responses, database rows, or JWTs (see our JWT decoder for those) without needing to open a REPL or write a one-off script.
Limitations
Only Gregorian-calendar dates within the range JavaScript's Date object supports are handled (roughly ±273,000 years from 1970, which covers every realistic use case). There's no support for custom calendars or leap-second-aware timekeeping.
FAQ
- Is this timestamp converter really free?
- Yes — completely free, with no limits and no account required. Everything runs locally in your browser.
- How does it know whether I entered seconds or milliseconds?
- By digit count: a 10-digit number is treated as seconds (the standard Unix timestamp), a 13-digit number as milliseconds (the JavaScript Date.now() convention). This covers virtually every real-world timestamp until the year 2286.
- What timezone are the converted dates in?
- Both are shown: UTC (timezone-independent, useful for logs and APIs) and your browser's local timezone (useful for reading it as a person would). The ISO 8601 string is always UTC.
- Can I convert a date back into a timestamp?
- Yes — the second box accepts any date format your browser understands (ISO 8601 like 2024-01-01T00:00:00Z, or a plain human-readable date) and converts it to a Unix timestamp in seconds.