Unix Timestamp Converter
Convert Unix epoch timestamps in seconds or milliseconds to human-readable UTC and local dates, or convert calendar dates to Unix timestamps.
How to Use the Unix Timestamp Converter
Enter an epoch timestamp (10 digits for seconds or 13 digits for milliseconds) to convert it to ISO 8601, UTC, and your local timezone. You can also switch tabs to enter any human date and get its epoch timestamp.
Formula & Calculation Method
Unix Time = Number of seconds elapsed since 1970-01-01T00:00:00Z (UTC)Standard POSIX epoch tracks elapsed seconds (or milliseconds) excluding leap seconds.
Calculation Examples
Timestamp 0
The exact start of the Unix Epoch.
Modern Epoch Seconds
10-digit second timestamp.
Frequently Asked Questions
How do I tell if a timestamp is in seconds or milliseconds?
10-digit timestamps (e.g. 1700000000) represent seconds. 13-digit timestamps (e.g. 1700000000000) represent milliseconds. Our converter allows you to toggle or auto-detect.
Can this tool handle dates before 1970?
Yes. Timestamps before January 1, 1970 are represented by negative numbers (e.g. -86400 corresponds to December 31, 1969).
Which timezone does the converter display?
It provides both universal UTC / ISO 8601 timestamps and your local computer/device timezone side-by-side.