Free browser-based CSV tools
Fix broken CSV files directly in your browser.
No upload. No signup. Your data never leaves your device.
Drop a CSV to diagnose
CSV, TSV, or text. Processed locally — the file is never uploaded.
Popular CSV repair tools
- CSV Validator & RepairDiagnose structure errors and download a repaired RFC 4180 file.
- CSV Encoding FixerReinterpret legacy encodings and save a clean UTF-8 CSV.
- CSV Delimiter DetectorTell comma, semicolon, tab, and pipe files apart with confidence.
- CSV Delimiter ConverterConvert between comma, semicolon, tab, and pipe without breaking quotes.
- CSV Column Mismatch FinderFind rows with the wrong number of fields and pad or trim them.
- CSV Quote Error FinderLocate unclosed and bare quotes, then rewrite fields as valid CSV.
- CSV CleanerRemove duplicate rows, drop empty rows, and trim whitespace.
- Compare CSV FilesDiff two CSV files by ID, SKU, email, or any key column.
- CSV Leading Zero ToolPad ZIP codes, SKUs, and IDs so spreadsheet apps keep the zeros.
- CSV Scientific Notation ToolExpand identifier-like values and warn when precision is already gone.
Common CSV problems
Excel saved the file with a semicolon
In many European locales Excel writes CSV with semicolons because the comma is the decimal mark. Other tools then see a single column.
Open the toolAccented characters turned into é
That is UTF-8 bytes shown as Windows-1252, or the reverse. Reinterpret the bytes; do not search-and-replace the mojibake.
Open the toolZIP codes lost their leading zeros
Spreadsheets treat 02115 as the number 2115. Pad the column and quote it before the file is opened again.
Open the toolLong IDs became 1.23E+15
Excel stores numbers as 15-digit floats. If the original ID was already rounded, the missing digits cannot be invented.
Open the toolA quote swallowed half the file
An unclosed quote makes every following line part of one field. The quote fixer recovers the remainder and rewrites RFC 4180 quoting.
Open the toolSome rows have extra commas
Unquoted addresses and comments add fields. The mismatch finder shows which rows drifted from the header width.
Open the tool
Your files never leave your device
Each tool reads the file you select with the browser File API and ArrayBuffer. Parsing, diagnosis, and repair happen in JavaScript in this tab. Downloading a result creates a local Blob — it is not posted to a server. That is why you can work on customer lists and payroll exports without sending them to us. We cannot see the contents, because they are never transmitted.
- No CSV upload API
- No account, cookie wall, or tracking pixel required to use the tools
- Original files stay on disk; downloads are new copies
How it works
01
Choose a tool or drop a file
The homepage diagnoses structure, encoding, and delimiter.
02
Review the summary
You see filename, size, encoding, delimiter, rows, columns, and problems before anything is rewritten.
03
Preview the repair
Nothing is saved until you download. The original file is not overwritten.
04
Download a copy
Get a new CSV with RFC 4180 quoting, the delimiter you asked for, and optional UTF-8 BOM.
FAQ
Do you upload my CSV?
No. The browser reads the file with the File API. Repair runs in JavaScript on this page. There is no upload endpoint for file contents.
Is an account required?
No. There is nothing to sign in to. Download is a local Blob saved through the browser.
What size files can I repair?
Typical exports of a few megabytes are fine. Very large files (tens of megabytes) may take a moment and can be truncated for diagnosis if they exceed the in-browser safety limit.
Will this restore IDs Excel already rounded?
Only if the digits are still in the file. Scientific notation with three significant digits cannot be turned back into a 16-digit identifier.
Does it work with Excel and Google Sheets?
Yes. Download UTF-8 (optional BOM) with CRLF if you need Excel on Windows. Google Sheets imports UTF-8 CSV directly.