How to Convert Excel XLSX Spreadsheets to CSV

Learn how to convert XLSX spreadsheets to CSV online or in Excel, plus what happens with multi-sheet workbooks.

Convert XLSX to CSV in a few clicks

To convert an Excel XLSX file to CSV, upload the spreadsheet, choose CSV as the output format, and download the converted file. Most online tools follow the same basic flow: upload, select CSV, convert, then download.

If you are using MK Convert, the conversion happens in your browser with nothing uploaded to a server, which is useful when you want a quick, private file conversion.

What CSV changes from XLSX

XLSX is a spreadsheet format that can store multiple sheets, formulas, formatting, charts, and other workbook features. CSV is a plain-text format that stores rows and columns as comma-separated values, so it is much simpler and more limited. Because of that, a CSV file usually preserves the visible data from one sheet, but not workbook formatting or multi-sheet structure.

Excel warns that only the active sheet will be saved when you export to CSV, because CSV files can only represent one sheet at a time.

How to convert XLSX to CSV in Microsoft Excel

1. Open the XLSX file in Excel.
2. Go to File > Save As.
3. Choose where to save the file.
4. In the file type list, select CSV (Comma delimited) (*.csv).
5. Click Save.
6. If Excel warns that only the active sheet will be saved, click OK if that is what you want.

This method is the most direct option if you already have Excel installed.

How to convert XLSX to CSV online

Online converters use a similar process: upload your XLSX file, select CSV, and download the result. Some tools also support batch conversion or multiple worksheets.

1. Upload your XLSX file from your computer or drag and drop it.
2. Select CSV as the output format.
3. Click Convert and wait for the file to process.
4. Download the CSV file when it is ready.

What to watch for before converting

• One sheet only: a single CSV file can store only one worksheet at a time, so multi-sheet workbooks need special handling.
• Formatting is not kept: CSV stores data, not fonts, colors, formulas, or charts.
• Sheet selection matters: if your workbook has several sheets, choose the one you need before saving or converting.
• Delimiter settings may matter: some converters let you choose comma, semicolon, or tab depending on how the CSV will be used.

How to handle multi-sheet workbooks

If your XLSX file has several sheets, you generally have two choices: export each sheet separately or merge the sheets into one CSV if your tool supports it. Some converters create separate CSV files for each sheet, while others offer a combined or merged mode.

If you only need one sheet, select that sheet first in Excel or use a converter that lets you choose the worksheet explicitly.

When to use an online converter vs Excel

• Use Excel when you already have the file open and want a simple one-sheet export.
• Use an online converter when you want a fast, browser-based option without installing software.
• Use MK Convert when you want the conversion to stay in your browser with nothing uploaded to a server.

Quick checklist for a clean CSV export

• Confirm which sheet you want to export.
• Check whether commas, semicolons, or tabs are best for your next app.
• Save a copy of the original XLSX if you need formatting or formulas later.
• Open the CSV after conversion to confirm the rows and columns look correct.

If you need a fast, privacy-focused workflow, MK Convert lets you convert XLSX to CSV directly in the browser, so the file never needs to be uploaded to a server.