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Runs in your browserConvert Excel to CSV
Excel's Save As gives you one CSV at a time, and only the tab you're looking at. This does every tab in one pass and hands them back as a zip. Older .xls files can't be read here — save them as .xlsx in Excel first.
Your file stays on this computer. There’s no upload button here, because there’s nowhere to send it. This tool runs inside the page you opened — like a calculator on a web page, it keeps working once it has loaded. How this works, and how to check it →
How to use it
- Choose your .xlsx file.
- Convert every tab, or just the first.
- Pick a delimiter if you need semicolons instead of commas, then click Convert.
Questions
Is my file uploaded anywhere?
No. The whole tool is inside this page, so the work happens on your computer. There is no server to send it to. If you'd rather check than take our word for it: use the tool once, on a sample file, with the settings you want. Then turn off your wi-fi and do exactly the same thing again in that tab, without reloading. It still works, because everything it needs is already here.
What happens to dates?
They're written as 2026-09-07, and dates carrying a time keep it as 2026-09-07 14:30:00. That format sorts correctly as text and means the same thing everywhere. 03/04/2026 is two different days depending on the country reading it.
Do formulas come out as formulas or as values?
As values — the result Excel last calculated, which is what you want in a CSV. A CSV has no concept of a formula, so exporting the formula text would produce a file full of unusable =SUM() strings.
Will it open an old .xls file?
No — .xls and .xlsx are different formats, despite the names. Open the file in Excel and choose File → Save As → Excel Workbook (.xlsx), then come back. If you don't have Excel, LibreOffice opens .xls and saves .xlsx for free.
Why does it warn me about cells starting with an equals sign?
Because a cell that starts with =, +, - or @ turns back into a formula when the CSV is opened. A workbook can hold "=SUM(A1:A2)" as harmless text, and the same characters in a CSV are a formula again. Where the workbook came from someone else, that's a way to get something running inside your spreadsheet. Turn on "Stop Excel treating cells that start with = as formulas" and those cells get an apostrophe, so Excel shows them as text. Leave it off for figures you produced yourself, because a value like -50 turns into text as well.