Excel Editor — Edit XLSX & CSV Online
Edit xlsx, xls and csv files without Excel: change cells, add rows, columns and sheets, use SUM and AVERAGE formulas, undo, and save as xlsx or CSV. Files stay in your browser.
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How to use
Everything you enter is processed only in this browser.
Open an Excel (xlsx, xls) or CSV file, or start with a blank sheet
Select a cell and type a value or a formula such as =SUM(A1:A5); add or delete rows, columns and sheets
Use Undo to try changes safely, then save as xlsx or CSV
How it works and good to know
xlsx, xlsm and csv are read directly; for older xls and ods the SheetJS reader (Apache-2.0) is downloaded only when such a file is opened. Files can be up to 20 MB, with up to 300,000 filled cells, 50,000 rows and 200 columns per sheet — if a file is bigger, only the first part opens and the screen says so (saving then keeps only that part). SUM, AVERAGE, MIN, MAX, COUNT, cell and cross-sheet references, arithmetic, powers, %, & and parentheses are calculated instantly; invalid formulas show #ERROR!, #NAME?, #DIV/0! or #REF!, and cells that refer to each other show #CIRC. Other functions show the result stored in the file and their formula text is saved unchanged. Inserting or deleting rows, columns and sheets updates formula references the way Excel does. Formatting, charts and merged cells cannot be edited; merged cells are unmerged when opening, and saving keeps values and formulas only. xlsx keeps both formulas and calculated values; CSV (UTF-8 with BOM) keeps the calculated values of the current sheet. Files stay in this browser and are never sent to a server.