About the CSV Tools
CSV Tools is a small workbench for everyday clean-up of comma-separated and tab-separated data. Open a file or paste text, and it detects the delimiter for you. Then choose what to do: change the delimiter, for example from semicolons to commas or from CSV to TSV, transpose rows into columns, keep only some columns, delete columns, reorder or swap them, add a column with a fixed value, remove empty rows, remove duplicate rows or trim stray spaces. Columns can be chosen by number, by range or by header name. The reader understands quoted cells, doubled quotes and line breaks inside quotes, and the writer quotes cells only when it has to. The result can be copied or downloaded. All of it runs in your browser, so your data never leaves your device.
Updated September 2026
How to use the CSV Tools
- 1Open a CSV or TSV file, or paste your data into the box.
- 2Check the detected delimiter and change it if the guess is wrong.
- 3Choose what to do, such as change the delimiter, transpose or delete columns.
- 4For column jobs, type the columns by number, range or header name.
- 5Copy the result or download it as a CSV or TSV file.
What CSV files are and why they need fixing
CSV stands for comma-separated values, a plain text way of storing a table: one row per line and one delimiter between cells. It is the format that most spreadsheets, databases, shops and mailing systems can import and export, which is why it is everywhere. It also has no strict standard in practice. Some programs use semicolons because commas are decimal marks in their region, some use tabs, and some add quotes in unusual ways.
So a file that opens neatly in one program can arrive as a single long column in another. The quick fixes are the ones this tool offers: change the delimiter, remove columns you do not need, put columns in the order an import form expects and clean out blanks.
The jobs you can do
- Change the delimiter: comma to semicolon, tab or pipe and back.
- Transpose: swap rows and columns for reports and charts.
- Keep or delete columns: drop private or unused fields before sharing.
- Reorder or swap: match the column order that another system asks for.
- Add a column: label every row with a source, a date or a status.
- Clean up: remove empty rows, remove duplicate rows and trim spaces.
Choosing columns
Columns can be typed as numbers starting from 1, as ranges such as 2-5 or as header names when your first row holds headers. Separate several choices with commas. If a number is out of range or a name is not found, the tool says which one, so you can fix it without guessing.
Excel and Google Sheets can save CSV files, but some add a byte order mark at the start of the file. The tool removes it when reading so your first header name matches what you see.
Tips and related tools
Keep the original file until you have checked the result, and open the output in your spreadsheet program to confirm that the columns line up. To convert a CSV to another data format, CSV to JSON produces JSON, and Sort Lines and Remove Duplicate Lines help with plain text lists. Word Frequency Counter counts words in a column you paste in, and JSON Formatter tidies the JSON that comes out.
Features
- Delimiter detection for comma, semicolon, tab and pipe
- Convert between CSV, TSV and other delimiters
- Transpose rows and columns
- Keep, delete, reorder and swap columns
- Pick columns by number, range or header name
- Add a column with a fixed value
- Remove empty rows and duplicate rows, trim spaces
- Correct quote handling, files stay on your device
Frequently asked questions
How do I change the delimiter of a CSV file?
Open the file, leave the first option on Change the delimiter, and choose the delimiter you want for the result. Semicolon-separated files from European spreadsheets can become comma-separated in one step, and you can pick tab to make a TSV file.
How do I delete a column from a CSV file?
Choose Delete columns and type the column number, such as 3, a range such as 2-4 or the header name. Tick First row is headers to use names. The remaining columns keep their order.
How do I swap or reorder columns?
Choose Reorder or swap columns and type every column you want in the new order. To swap the first two columns of a four-column file, type 2,1,3,4. You can also repeat a column to duplicate it.
What does transpose do?
It turns rows into columns and columns into rows, so a table with 3 rows and 5 columns becomes 5 rows and 3 columns. Short rows are padded with empty cells first so nothing shifts out of place.
Does it handle commas inside quotes?
Yes. Cells wrapped in double quotes can contain the delimiter, doubled quotes and line breaks, and they are read as one cell. When writing, the tool adds quotes around any cell that needs them, so the file stays valid.
Is my data uploaded anywhere?
No. The file is read and changed in your browser. Nothing is sent to a server, which matters for customer lists, exports and other private data.
How large a file can it handle?
Files up to about five million characters work in most browsers, which is tens of thousands of rows of typical data. For much bigger files use a command-line tool or split the file first.