Normalise dates in a source dossier

Do these timestamps describe the same instant?

Publication, effective and access dates have different roles. Retaining role and precision prevents a misleading chronology; normalisation does not certify the producer’s clock.

1. Keep original text

   Record field, language, convention and role. Keep 2026-10 as a month; do not invent a day or hour.

2. Identify the offset

   Z or +02:00 locates an instant. Local time needs a zone and date-specific rules; a country or your computer’s setting is insufficient.

3. Preserve ambiguity

   03/04/2026 needs the producer’s convention. Clock changes can repeat or skip local times; record uncertainty instead of silently choosing.

4. Retain precision

   Keep original, normalised value, zone, offset and rule version. Sort determined instants separately from calendar dates.

Normalise a date list

Processed in your browser; values are not sent to the server. One value per line, up to 100 lines. Examples are calculation cases.

Supported: YYYY-MM-DD, partial year or month, and timestamps with seconds and Z or ±HH:MM offset. Fractions of 1–9 digits are retained. Local times are not converted; leap seconds need separate treatment. Input order is preserved.

Situations and decisions

Typical situations for preparing a check. They do not describe completed assignments or actual observations.

Record to retain

• Original text, field and date role.
• Precision, explicit offset or identified zone.
• Normalised value, convention and rule version.
• Ambiguities, partial dates and refused conversions.

Official references

• IETF — RFC 3339
• IANA — Time Zone Database

Related source profiles

• IANA — Time Zone Database
• Wayback Machine
• ICANN Lookup
• RIPEstat
• ClinicalTrials.gov
• WHO ICTRP — registre des essais
• BODACC
• TED — Tenders Electronic Daily

Related protocols

• Reconstruct a timeline of public signals
• Keep a reproducible version of public data
• Document a source translation

Checks before reaching a conclusion

• Is each date’s role explicit?
• Is the offset sourced?
• Is original precision retained?
• Are ambiguous values kept out of instant sorting?