Edit CSV online without changing your data
Open a .csv file or paste CSV text, edit cells in the table, add or delete rows and
columns, and download the result. The editor treats every cell as text: it does not detect
numbers or dates, does not trim spaces and does not reformat anything you did not change.
Why values stay exactly as written
Spreadsheet applications such as Excel can change CSV data when they open it - for example by
removing leading zeros, showing long numbers in scientific notation or turning date-like text
into dates (Microsoft documents this in its support article on keeping leading zeros and large
numbers). Here, 00123 stays 00123, 03/04 stays
03/04 and 12345678901234567890 stays exactly that.
If you open a file and download it without editing, you get a byte-for-byte identical file. After edits, the cells you did not touch keep their exact values. Editing a cell or inserting and deleting rows or columns can change quoting and line structure around the change; edited cells are quoted only when the CSV format requires it (or when the original cell was quoted).
Supported files
UTF-8 text files (with or without a byte-order mark) separated by commas, semicolons, tabs or pipes. The delimiter is detected automatically and can be changed. Files that are not valid UTF-8, or that are not well-formed CSV - for example a quoted field that is never closed - are reported with the line and column instead of being guessed or repaired.
Supported up to 10 MB or 1,000,000 cells, whichever limit is reached first.
Formula warnings
Cells that start with =, +, -, @, a tab or a
carriage return can be interpreted as formulas by spreadsheet applications. The editor marks such
cells and shows how many there are, but never changes them. Plain numbers such as
-12.5 are not flagged.
How privacy works here
Everything runs in your browser. There is no account, no history and no save or share link, and
the page's Content Security Policy (connect-src 'none') blocks it from making network
requests. Like any website, the host receives standard request information when the page itself
is loaded - never the CSV you open. See the privacy notice.
FAQ
Does the editor upload my CSV?
No. The file is read and edited inside your browser and is not uploaded or stored.
Will it remove leading zeros or convert dates?
No. Every cell is kept as text exactly as written unless you edit it.
Why is my file rejected?
The editor only opens valid UTF-8 files and well-formed CSV. Rather than guessing, it tells you the line, column and reason so you can fix the source.
How large can the CSV file be?
Supported up to 10 MB or 1,000,000 cells, whichever limit is reached first.
Can I undo an edit?
Press Escape to cancel an edit in progress. To discard all edits, use Reset to original.
Does it support Excel files or formulas?
No. It edits CSV text only; formulas are shown as plain text and never calculated.