Unix Timestamp Converter
Convert between timestamps and dates in both directions, with UTC, local time, zone offset, weekday, relative time and seven common formats at once.
How to Use
- Enter a timestamp or date
Plain digits are treated as a timestamp — 10 digits or fewer means seconds, 11 or more means milliseconds; anything with - or : is parsed as a date-time. Results refresh as you type.
- Read the results
UTC and local time sit side by side; the zone offset tells you which zone this machine is in, while weekday and relative time help judge how recent a value is.
- Copy a format
The table below lists seven notations including ISO 8601, RFC 2822, HTTP date and SQL datetime — select and paste straight into code or config.
FAQ
Why can't I pass a timestamp straight to new Date()?
Because the Date constructor treats numbers as milliseconds, while a Unix timestamp is almost always seconds. new Date(1750000000) gives 1970-01-21, not 2025. The correct form is new Date(ts * 1000), or check the digit count first — which is exactly what this tool automates.
Does the year 2038 problem show up here?
No. That problem comes from storing seconds in a signed 32-bit integer, which overflows at 2147483647 (2038-01-19 03:14:07 UTC). Browser Date uses 64-bit floats for milliseconds and reaches far past year 200000, so nothing overflows here. But if your backend stores timestamps in int32, it will break after 2038.
How do I see the gap between local time and UTC?
The zone offset field shows the current difference, such as UTC+08:00. China has no daylight saving and stays at +08:00 all year; Europe and North America shift, so the same machine reports a different offset in March and November. Cross-zone reconciliation should always use UTC.
What difference does writing a zone make?
Z or +08:00 marks a fixed instant that does not depend on the machine. Without it the string is read in the browser's zone, so the same text yields different timestamps on machines in different zones. Always include a zone when passing values between systems.