How to use
- Choose the direction: Timestamp → date, or Date → timestamp.
- Choose the unit: Unix seconds or Unix milliseconds.
- Enter a timestamp such as 1791203400, or a date-time such as 2026-10-05T12:30:00Z. Insert current time fills in the present moment.
- Select Convert, or press Ctrl+Enter (⌘+Enter on Mac) in the input box.
Unix time in seconds and milliseconds
A Unix timestamp counts the time since 1970-01-01T00:00:00Z (the Unix epoch). Most systems and APIs use seconds (for example 1791203400, as in JWT exp and iat claims), while JavaScript and many databases use milliseconds (1791203400000).
This tool never guesses the unit from the number of digits: you choose seconds or milliseconds, so a value is never silently misread. Negative timestamps are dates before 1970.
Exact results in UTC
Results are shown in UTC as ISO 8601, which is unambiguous and the same for everyone. Your device's local time is shown as a second, clearly labelled reading.
Seconds may have up to three decimal places (milliseconds); milliseconds must be whole numbers. Values with more precision are rejected instead of being rounded, and conversions use exact decimal arithmetic.
Dates must include a time zone
Enter dates as ISO 8601 with Z (UTC) or an offset, for example 2026-10-05T12:30:00Z or 2026-10-05T19:30:00+07:00. A date-time without a zone could mean different instants on different computers, so it is rejected rather than guessed as local time.
Supported years are 0000–9999. Leap seconds (:60) cannot be represented in Unix time. Results cover the full range of JavaScript dates, about 275,000 years either side of 1970.
FAQ
- How do I know if my timestamp is in seconds or milliseconds?
- Present-day timestamps have 10 digits in seconds and 13 digits in milliseconds. If a conversion lands in 1970 or tens of thousands of years in the future, try the other unit.
- Is my data sent anywhere?
- No. Conversions run in your browser. Nothing you enter is sent to a server, stored, or added to the page URL.
- Why was my date rejected?
- Common reasons are a missing time zone (add Z or an offset like +07:00), a space instead of the T separator, an impossible date such as February 30, or more than three fractional second digits.