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CSV Format Checker Online

Paste CSV and validate the structure fast: delimiter detection, quote/escape rules, row/column consistency, and a clear list of where the problems are.

Category: Data · URL: /tools/csv-format-checker-online.html
Tip: If your CSV import fails, turn on Strict quoting to catch “quote-in-the-middle” problems.
Privacy: runs locally in your browser. No uploads, no tracking scripts.

How to use

Use this tool to validate CSV structure and pinpoint formatting issues.

  1. Paste your CSV into the input box.
  2. Choose Delimiter: Auto (or force one) and keep the quote char as " unless your file differs.
  3. Click Check CSV to get a compact report (rows, columns, errors, and line/column hints).
  4. Optional: enable Include normalized CSV to output a cleaned version using consistent quoting.
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Secondary intents covered: Confirm whether a pasted CSV is structurally valid, Detect the delimiter (comma/tab/semicolon/pipe), Find rows with inconsistent column counts, Spot unclosed quotes and bad quote escaping, Generate a normalized CSV output for import, Prepare a CSV before loading into Excel/Sheets/SQL, Troubleshoot why a CSV import fails, Validate a header row and column count expectations

FAQ

What does this CSV format checker validate?

It checks delimiter consistency, quote/escape correctness, and whether each row has the same number of columns.

Does it support commas inside quoted fields?

Yes. Values like "hello, world" are treated as a single field when quoting is correct.

What is “Strict quoting”?

Strict mode flags cases like characters after a closing quote or quotes appearing inside unquoted fields.

Can it detect the delimiter automatically?

Yes. Auto-detect picks from comma, tab, semicolon, or pipe based on the first row.

Why do I see “Inconsistent column count” errors?

At least one row has more or fewer fields than the first row (often caused by missing/extra delimiters or broken quotes).

Will this tool upload my CSV anywhere?

No. Everything runs locally in your browser; the tool does not send network requests.

What does “Include normalized CSV” do?

It outputs a cleaned CSV where fields are quoted only when needed and quotes are escaped correctly.