Normalize CSV dates without swapping month and day

Step-by-step approach

Identify the date convention in the source system before conversion.
Prefer unambiguous year-first ISO dates such as 2026-11-02.
Use the date normalizer for its explicitly supported year-first patterns.
Leave ambiguous 03/04/2026 values unchanged rather than guessing.
Review skipped rows and validate them against the original business source.

Try the matching tool

Open Date Normalizer to work on a local copy. Review the result before importing it elsewhere.

What this does not solve

Browser tools can validate known structures and transform available data, but cannot restore deleted or corrupted bytes, infer unknown business facts, or guarantee that a target system will import every field as intended.