Timestamp Converter
Convert between Unix timestamps and human-readable dates. Auto-detects seconds vs. milliseconds.
Curious why computers count time this way? Read: Understanding Unix Timestamps
Seconds or milliseconds — both work.
Your local timezone.
A Unix timestamp counts the seconds elapsed since midnight UTC on January 1, 1970 — a fixed reference point programmers call "the epoch." It's the format behind timestamps in databases, log files, and API responses, precisely because a plain integer is faster to compare and sort than parsing a date string every time.
This tool auto-detects whether you've entered seconds (10 digits) or milliseconds (13 digits, the format JavaScript's Date object uses internally) and converts either direction — timestamp to readable date, or date to timestamp — entirely in your browser.
Common questions
Why do some systems use seconds and others milliseconds?+
Unix and most databases traditionally use seconds-based timestamps. JavaScript's Date object specifically uses milliseconds internally for finer precision. Mixing the two up — treating a millisecond timestamp as seconds or vice versa — is one of the most common timestamp bugs, landing decades off from the intended date.
What does the 'exp' field in a JWT actually mean?+
It's a Unix timestamp, in seconds, marking when the token expires. Pasting that raw number here converts it to an actual readable date — useful when debugging why a token expired earlier or later than expected.
Does this account for timezones?+
Unix timestamps themselves are timezone-independent — they represent a single moment in time globally. This tool displays that moment in both UTC and your browser's local timezone, so you can see it either way.
Can this handle dates before 1970?+
Yes, negative timestamps represent moments before the epoch and are valid — the conversion works the same in both directions, just producing a negative number for dates before January 1, 1970.