ISO 8601 Date Interval Format Validator

Validate a practical ISO 8601 interval subset of the form start/end. It checks Gregorian calendar dates (including leap years), clock and UTC-offset ranges, reduced-precision dates, and non-mixed calendar or week durations; it does not compare endpoint chronology.

Description

Validate a practical ISO 8601 start/end interval subset with real Gregorian dates, clock ranges, offsets, and durations.

Validate a practical ISO 8601 interval subset of the form start/end. It checks Gregorian calendar dates (including leap years), clock and UTC-offset ranges, reduced-precision dates, and non-mixed calendar or week durations; it does not compare endpoint chronology.

When to use ISO 8601 Date Interval Format Validator

  • Validate a practical ISO 8601 start/end interval subset with real Gregorian dates, clock ranges, offsets, and durations.
  • Apply the same explicit rule consistently during ingest, quality control, reporting, or preservation planning.
  • Expose records that need human review without silently rewriting the source data.

How the calculation works

Calendar validation rejects dates such as 2025-02-29 and accepts 2024-02-29; a syntactically valid interval is not necessarily chronological.

interval = start/end; at most one component may be a duration

Interpreting the result

Calendar validation rejects dates such as 2025-02-29 and accepts 2024-02-29; a syntactically valid interval is not necessarily chronological.

Assumptions and limitations

  • The supported subset omits expanded years, ordinal/week dates, leap-second 60, open intervals, repeating intervals, and fractional units other than seconds.
  • Preserve the original value and record the rule version when using this result in an archival workflow.
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