Convert .xlsx to CSV in your browser, without uploading it

How to convert a spreadsheet to CSV

1. Open Sheets and open your .xlsx, .xls or .tsv file, or drop it onto the window.
2. Switch to the tab you want to export, since CSV only holds one flat grid.
3. Use the export menu's "Save as .csv" option and save the file to your computer.

What the CSV export actually does

The export writes each row and column as plain, comma-separated text, using every cell's last calculated value rather than the formula that produced it, because CSV has no way to represent a formula. Cells that look like they could start a formula in another program are escaped, so a spreadsheet built from this CSV can't run anything unexpected when someone opens it. Number and date formatting is not preserved; a CSV cell is always plain text or a plain number.

Converting the other way: CSV or .tsv into a workbook

Sheets also opens .csv and .tsv files directly, the same way you'd open an .xlsx: drag the file onto the app window or use the open menu. Once it's open you can use formulas, formatting, charts and pivot tables on data that started life as a plain export from another program, then save it back as .xlsx once you want to keep those features, or as .csv again if you only need the plain values.

What to check before you rely on the CSV

• A value that must keep a leading zero, such as a ZIP code, needs to be entered as text in Sheets first (a leading apostrophe, or a cell formatted as text). A value already stored as a plain number won't get its leading zero back just because you exported it.
• Hidden rows and columns are still included in the export; CSV has no concept of "hidden".
• Charts and pivot tables live in the app and aren't part of a CSV, since CSV can only hold a plain grid of values.

Why do it in the browser

A workbook of client numbers, salaries or account balances is exactly the kind of file you don't want to hand to an unknown converter site. Sheets reads, converts and writes the file inside the page you already have open, with nothing sent to a server. For sending the finished CSV to someone else, the File Safe can lock it in a password-protected .vault file first.