Data

CSV Validator

Check CSV quoting and record widths, reporting row and column counts with header warnings.

✓ Browser-local processing

Result

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How to use CSV Validator

Find malformed quotes or mismatched field counts before importing data. Validation uses your selected delimiter and reports header quality separately from syntactic CSV correctness.

Paste CSV and specify its delimiter.
Select Run tool to check quoting and compare record widths.
Review the result, then copy it or download the generated file.

Good to know

Up to 200,000 characters, 5,001 records, 200 columns, and 50,000 characters per cell. Quotes must follow CSV rules; output CSV uses formula-safe apostrophe prefixes where needed.
Checks syntax and table shape only, not data types, business rules, spreadsheet formulas, or whether the first record is truly a header.

Common questions

Is a duplicated header invalid CSV?

It can be syntactically valid CSV but problematic for record conversion, so it is reported as a header warning.

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