Check and fix a CSV file
Find encoding, delimiter, row and header problems in a CSV file, see where each one is, and download a clean UTF-8 copy.
Processed in your browser
Drop a CSV file here
CSV, TSV or TXT. You can also paste CSV text anywhere on this page.
Formats and limits
- Opens
- CSV (.csv), TSV (.tsv), Text (.txt), Pasted text
- Saves
- CSV in UTF-8 (.csv, or .tsv with the tab delimiter)
- Size
- Tested with a 100 MB UTF-8 file in Chromium (the engine Chrome and Edge use) on Linux. Not tested yet in Firefox or Safari.
How to use it
- Choose, drop or paste a CSV, TSV or TXT file. The check starts at once.
- Read the results: the encoding, delimiter and line endings, and each problem with its row or column. The preview shows the first 200 rows.
- If the tool can only guess the encoding, pick the one that makes the preview read correctly.
- Choose the delimiter and line endings for the clean copy, then select Download clean CSV.
What happens to your file
Processed in your browser
- Your files are processed in this browser tab. They aren't sent to our servers or to anyone else.
- The tool's code comes from greatestfiletools.com and uses only features built into your browser.
- Copies of your files and results aren't saved on this device, apart from what you download. The site stores your cookie choice, plus Google Analytics cookies if you accept them.
- If you accept analytics cookies, Google Analytics records your visit. It doesn't receive your files or file names.
Checked on October 17, 2026 in Chromium, Firefox and WebKit by an automated test that records the browser's requests while it processes sample files. How the check works.
Report a problem with this tool. Please don't attach files that contain personal information.
Known limitations
- Delimiters it detects: comma, semicolon, tab and pipe.
- Encodings it reads: UTF-8, UTF-16 (LE and BE), Windows-1252, Windows-1251, ISO-8859-2, Shift_JIS and GBK. Unless the file is valid UTF-8 or starts with a byte-order mark, the encoding is a guess you confirm.
- Bytes that can't be read in the file's encoding, for example in a file that mixes two encodings, are reported, not repaired: they become the replacement character (�) in the clean copy.
- Text after a closing quote, as in "ab"cd, is read as abcd and reported.
- A quoted cell that never closes turns off the download until that row is fixed.
- Rows with a different number of cells, blank or repeated column names and empty columns are reported, not changed.
- Excel workbooks (.xlsx, .xls) and other binary files aren't read: save them as CSV first.
- Line breaks inside quoted cells are kept as they are; the line-ending setting applies between rows.
Questions
How do I know if a CSV file is UTF-8 encoded?
Open it here. Unless the file starts with a UTF-16 byte-order mark or looks like UTF-16 text, the tool checks every byte against the UTF-8 rules and says whether the whole file is valid UTF-8. If it isn't, it shows the byte offset and row of the first invalid sequence, and how many invalid sequences there are.
How can I convert a CSV file to UTF-8?
Open it here and select Download clean CSV: the copy is always UTF-8. If the file isn't UTF-8 and has no byte-order mark, the tool can only guess its encoding, so it asks you to confirm it with a preview first. It reads UTF-16, Windows-1252, Windows-1251, ISO-8859-2, Shift_JIS and GBK.
Why is my CSV file not displaying correctly?
The check results show the file's encoding, delimiter and line endings, so you can compare them with what your app expects. They also list problems such as rows with a different number of cells, quoted cells that never close and bytes that can't be read, each with its row or column.
How can I view a CSV file in my web browser?
Open it here. The preview shows the first 200 rows as a table, split by the delimiter the tool found, and the file is read in this browser tab.