Excel's Save As dialog exports only the active sheet to CSV, and depending on the version and region it may pick a semicolon or a legacy encoding. When a workbook has twelve monthly tabs, that means twelve rounds of switching sheets and saving. This converter exports every sheet in one go, each to its own CSV file, in UTF-8 and with the delimiter you choose.
It reads modern .xlsx files, older .xls workbooks from Excel 97 to 2003 and OpenDocument .ods spreadsheets from LibreOffice. The workbook is opened by SheetJS running in a Web Worker in your browser, so payroll sheets, price lists and customer data are never sent anywhere.
What ends up in the CSV
A spreadsheet cell has two faces: the stored value and the text you see. A date is stored as a serial number such as 45000 (15 March 2023), a percentage as 0.125, and a currency amount as a plain number with a format attached. This converter writes what Excel shows, the formatted text, so the CSV contains 2023-03-15 or 12.5% rather than raw serials and fractions. For a formula, the result saved in the file is written, not the formula itself.
Everything else a workbook can hold is left behind: styling, charts, images, comments, data validation and the formulas themselves. Empty rows and columns at the end of a sheet are trimmed, while empty cells inside the data are kept so the columns stay aligned. Sheets with no data at all are skipped.
Common uses
Importing into databases and apps
PostgreSQL, MySQL, SQLite and most SaaS import screens take CSV, not XLSX. Exporting each tab to UTF-8 CSV gives files they accept without encoding errors.
Processing data with code
Python's csv module, pandas.read_csv, R and command-line tools such as csvkit or awk read CSV natively. A plain-text file is also easy to diff and to keep under version control in Git.
Splitting a multi-sheet workbook
A workbook with a tab per region, month or product line becomes a set of separate CSV files named after the workbook and the sheet, such as sales-January.csv.
Delimiters, quoting and encoding
Choose Comma, Semicolon, Tab or Pipe under Delimiter. The output follows RFC 4180: a field is quoted only when it contains the delimiter, a double quote or a line break, embedded quotes are doubled, and lines end with CRLF. Line breaks typed inside a cell with Alt+Enter are kept within the quoted field rather than starting a new record.
The file is always UTF-8, so Arabic, Chinese, emoji and accented names are preserved. Add a BOM for Excel writes a byte order mark at the start, which helps Excel recognise UTF-8 when someone double-clicks the CSV later; leave it off for databases and scripts, which may read the BOM as part of the first header. A workbook with a single non-empty sheet produces one file named after the workbook; with several, each file name gets the sheet name appended.
Protect against formula injection is on by default. A cell whose text starts with =, +, -, @, a tab or a carriage return could run as a formula when someone opens the CSV in a spreadsheet app, so it is written with a single quote in front and shows up as text. Signed numbers such as -5 are not changed. Switch it off for files that go to a script or database, where the quote would become part of the value.
Come usare questo strumento
- Drop .xlsx, .xls or .ods files onto the box, or click it to browse; files up to 50 MB are accepted.
- Under Options, pick the Delimiter, decide whether to Add a BOM for Excel, and keep Protect against formula injection on unless the files go to a script or database.
- Press Convert. Each non-empty sheet appears as its own CSV file in the results.
- Download the files one by one, or press Download all (.zip) to get every sheet together.
Limitations
- Password-protected workbooks cannot be opened; remove the password in Excel first.
- Formulas are not recalculated. If a file was produced by software that saved formulas without their results, those cells may come out empty.
- Merged cells keep their value in the top-left cell only; the other cells of the merge are empty.
- Hidden sheets, rows and columns are exported like visible ones.
- Numbers are written as displayed, so a cell formatted to two decimals exports rounded to two decimals. Widen the number format in Excel first if you need full precision.