Unix Timestamp Converter
Convert Unix epoch seconds or milliseconds to readable dates and ISO 8601 timestamps.
Unix time and the epoch
Unix time counts elapsed seconds from 1970-01-01T00:00:00Z, ignoring leap seconds. It gives applications and APIs a compact numeric way to represent an instant independently of display format or local time zone.
JavaScript’s Date API uses milliseconds rather than seconds. A typical current Unix timestamp therefore has 10 digits in seconds or 13 digits in milliseconds. This converter detects the common form and always displays both values so the unit is explicit.
Avoiding time-zone mistakes
Include Z for UTC or an explicit offset such as +05:30 when entering an ISO 8601 date. A date-time without an offset may be interpreted in the browser’s local time zone, which can produce different epoch values on different machines.
Frequently Asked Questions
Are Unix timestamps measured in seconds or milliseconds?+
The Unix timestamp convention uses seconds since the epoch, while JavaScript and many APIs use milliseconds. The converter detects typical 13-digit millisecond values and exposes both forms.
What time zone is a Unix timestamp in?+
A timestamp is an absolute instant and has no local time zone. It is counted from the UTC epoch; the same instant can then be displayed in UTC or your local zone.
Can Unix timestamps represent dates before 1970?+
Yes, systems that support signed timestamps represent pre-epoch instants with negative values. Platform date-range limitations can still apply.
What is the Year 2038 problem?+
Older systems using signed 32-bit seconds overflow after 2038-01-19. Modern JavaScript dates and many 64-bit systems support a much wider range.