Unix Timestamp Converter
Convert a date and time to a Unix timestamp and back — seconds or milliseconds, local time or UTC.
Date & time → Unix
Unix → Date & time
Frequently Asked Questions
What is a Unix timestamp?
A Unix timestamp (also called epoch time) is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970, not counting leap seconds. It is a compact, timezone-independent way to represent a moment in time.
What is the difference between seconds and milliseconds?
Classic Unix time is measured in seconds (10 digits for current dates, e.g. 1751884800). Many programming languages and APIs — including JavaScript — use milliseconds instead (13 digits). This tool converts both, and can auto-detect which you paste.
Does the converter use my local time or UTC?
Both. When converting a date to a timestamp you choose whether your entered date is in your local timezone or UTC. When converting a timestamp back, the result is shown in your local time, in UTC, and as an ISO 8601 string.
Is anything sent to a server?
No. All conversions run entirely in your browser using your device clock. Nothing you type is uploaded, logged, or stored.
Why does the converted date look off by a few hours?
That is almost always a timezone mismatch. A timestamp is an absolute instant; the same instant shows different wall-clock times in different zones. Check whether you meant local time or UTC when entering a date.
What date range is supported?
The tool handles the full range JavaScript can represent — roughly 271,821 BC to 275,760 AD — including negative timestamps for dates before 1970.