How to use this office tool
Upload a spreadsheet and choose a sheet. The tool scans text-like values for common date patterns and reports when more than one pattern is present.
#177 · Validation & Quality Checks Tool
Detect Mixed Date Formats
Inspect spreadsheet text for inconsistent date patterns and download a CSV report showing detected formats and cell locations.
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What this tool does
Recognized patterns include YYYY-MM-DD, DD/MM/YYYY, MM/DD/YYYY, dot-separated dates, and month-name dates. Results are exported as CSV evidence.
Recognized patterns include YYYY-MM-DD, DD/MM/YYYY, MM/DD/YYYY, dot-separated dates, and month-name dates. Results are exported as CSV evidence.
Pattern detection cannot resolve every ambiguous date. For example, 03/04/2026 may represent either March 4 or April 3.
Supported formats
XLSX, XLS, CSV, and TSV are accepted where the operation supports them. Browser memory, parser support, and Excel worksheet limits apply.
| Format | Support |
|---|---|
| XLSX / XLS | Parsed locally; advanced workbook objects may not be preserved |
| CSV / TSV | Quoted fields supported; encoding is read by the browser |
Tips for better results
- Use ISO dates when exchanging data.
- Investigate ambiguous slash dates manually.
- Treat detection as a quality check, not date conversion.
FAQ
What counts as a mixed date format?
The report flags date-like text that follows different recognizable patterns within the scanned scope.
Can the tool tell whether 04/05/2026 is day-first?
No. Slash dates where both numbers are 12 or less are inherently ambiguous without outside context.
Are real Excel date serial numbers included?
Native date cells may be represented consistently by the parser; the main check focuses on visible text patterns.
Does this tool convert dates to one format?
No. It produces a diagnostic CSV report so you can review inconsistencies before conversion.
Can I scan all worksheets?
Yes. Select All sheets after the workbook has been parsed.
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Processing summary
| Stage | Action |
|---|---|
| Input | Validated and parsed locally |
| Output | A newly generated file is downloaded |
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