ISO 8601 Validator & Formatter
Validate a string
Not a valid ISO 8601 string.
- Normalized
- Date
- Time
- UTC offset
- Epoch seconds
Now, in every ISO 8601 format
- Extended
- Basic
- Date only
- Ordinal date
- Week date
Why ISO 8601
ISO 8601 orders date parts from largest to smallest — year, month, day, hour, minute,
second — so strings sort chronologically as plain text and parse without locale guesswork.
The extended format (2026-06-12T08:30:00+02:00) is what APIs should emit; the
basic format drops separators, and the ordinal and week-date forms express the same instant
by day-of-year or ISO week.
Always include an explicit offset (or Z for UTC) in stored timestamps — a
bare local time is ambiguous the moment it crosses a timezone. To turn an ISO string into an
integer for storage or comparison, use the epoch seconds shown above or the
epoch converter.