Check and Repair CSV Files Locally in Your Browser
Check delimiters, encoding, and uneven rows, then preview and download a clean UTF-8 CSV. Free, with no signup.
Your files stay private. Your CSV file contents are processed locally in your browser and are not uploaded. Always review cleaned output before relying on it.
Choose your CSV or TXT files
Select one file or a batch of files. Each file is processed locally in your browser.
Batch mode: diagnostics run for every file; preview/export uses the selected file.
Optional import precheck settings
Choose the CSV type to add extra review flags. Export still works for every profile.
Flags common file-format and Excel/import-readiness issues for review.
Argon flags common file-format and structure issues for review. It does not guarantee platform import behavior.
What are you trying to check?
These hints stay in your browser. They do not upload, store, or track your CSV contents.
Optional. This note stays in your browser and can be included in your local Precheck Report. Do not paste private CSV contents here.
Recommended: files under 25 MB. Larger files may be slower because processing runs in your browser.
What does the CSV checker inspect?
Choose a CSV or TXT file to see its detected delimiter, encoding, row count, column count, and structural warnings. Argon checks for rows with a different number of columns from the header and possible unclosed quoted fields. The precheck summary also flags blank or duplicate headers and values that Excel may change, including leading zeros and long numeric IDs.
Delimiter detection supports commas, semicolons, tabs, and pipes. Encoding detection recognizes UTF-8 and byte-order marks for UTF-8 and UTF-16, with Windows-1252 as a fallback for legacy text. Detection is a best estimate: you can change the delimiter or choose an encoding manually, including ISO-8859-1, then inspect the updated preview.
What CSV problems can this help diagnose?
- CSV opens in one column or uses the wrong delimiter. Check the detected separator before exporting a semicolon, tab, or pipe file as comma-delimited CSV. See the Excel delimiter guide.
- Rows have inconsistent columns. Review row warnings and the cleaned preview. Export pads short rows with blank cells and preserves overflow cells in Extra columns. Some split decimal-comma amounts are joined; review the result before using it.
- Accented or international characters appear wrong. Try the source encoding and review the decoded text. Replacement characters are flagged; characters already lost in the original cannot reliably be recovered. Read about garbled CSV characters.
- A CSV needs checking before import. Review header issues and Excel risks alongside the structural checks. These checks do not guarantee acceptance by another application. The CSV precheck guide explains what to review next.
Preview, then export a clean UTF-8 CSV
The cleaned preview shows up to 100 data rows. Export uses the full file, normalizes the delimiter to commas, quotes fields when needed, and preserves embedded line breaks. Blank header names receive generated names. You can include a UTF-8 byte-order mark for Excel. Review the download before importing it: Excel can still change identifiers or dates when opening a CSV directly.
Select several files to run diagnostics for each, switch between their previews, or download all cleaned CSVs. Your browser may ask you to allow multiple downloads. Files are read and processed locally; CSV contents are not sent to Argon. No account is required. For an old-versus-new review, use Compare two CSV files before importing.
See CSV Repair in 40 seconds
This recording shows a semicolon-delimited CSV being inspected, previewed, and exported. The current interface includes additional precheck controls.
Read the demo walkthrough
- Open CSV Repair and choose a CSV file from your computer.
- The tool detects a semicolon delimiter and UTF-8 encoding.
- Review the file diagnostics, then inspect the cleaned table preview.
- Download the cleaned file as comma-delimited UTF-8 CSV.