Timestamp Converter
Convert Unix timestamps (seconds, ms, µs, ns) to ISO 8601 in UTC and your local timezone — and back.
Now
About this tool
Paste a Unix epoch timestamp and the unit is auto-detected from its magnitude — seconds, milliseconds, microseconds, or nanoseconds — then converted to ISO 8601 in UTC and your browser's timezone, with a relative time. Date strings convert back to epoch values, and a live clock shows the current time in every format.
Useful for reading raw timestamps out of logs, database rows, and API payloads without firing up a REPL.
Frequently asked questions
How does it know whether I pasted seconds or milliseconds?+
By magnitude: 10-digit values are seconds (until year 5138), 13 digits are milliseconds, 16 microseconds, 19 nanoseconds. Today's date appearing means the guess was right.
Which timezone do the results use?+
Two are always shown: UTC (the ISO string with Z) and your browser's local timezone with its offset. Store and exchange UTC; localize only for display.
Do negative timestamps work?+
Yes — they represent times before 1970-01-01 UTC, e.g. -86400 is 1969-12-31.
What about the year 2038 problem?+
That limit applies to systems storing seconds in a signed 32-bit integer. JavaScript (and this tool) use 64-bit floats for milliseconds, which comfortably covers ±275,000 years.