Timestamp & Date Converter — Unix Timestamp, Date Format, ISO 8601, Date Diff & More
Timestamp & Date Converter
Convert between Unix timestamps and dates, format dates, calculate date differences, add/subtract time, find week numbers, and explore a calendar.
All processing happens locally in your browser — your data is never uploaded to any server.
Wrap literal text in [brackets], e.g. [GMT]. Click tokens to insert:
Timestamp → Date: Enter a Unix timestamp (seconds or milliseconds). The tool auto-detects the unit.
Date → Timestamp: Pick a date and time to get the Unix timestamp in seconds and milliseconds.
Week Number: Uses ISO 8601 week numbering (Monday as first day, Week 1 contains Jan 4).
Calendar: Navigate months with arrow buttons. Today is highlighted in blue.
What is a Unix timestamp?
A Unix timestamp counts the seconds elapsed since the epoch — 1970-01-01 00:00:00 UTC — and is the same number in every timezone: 0 is that moment everywhere on Earth, which is why timestamps sidestep the whole timezone question.
Unix time ignores leap seconds — every day is exactly 86,400 seconds — so it is not strict SI time; and systems that store it as a signed 32-bit integer overflow on 2038-01-19 03:14:07 UTC, the Y2038 problem.
