Which file formats can I upload?

Real .xlsx and legacy .xls workbooks, since SheetJS (the parsing library this tool uses) reads both into the same internal sheet format before exporting as CSV.

What happens with a workbook that has multiple sheets?

All sheet names appear as buttons above the output so you can pick which one to export; only one sheet converts to CSV at a time, matching how CSV itself represents a single flat table.

How are values with commas or quotes handled?

Any cell value containing a comma, double quote, or line break is wrapped in double quotes (with internal quotes doubled), following standard CSV quoting rules, so the output parses back correctly.

Does this tool upload my spreadsheet anywhere?

No. The file is read and converted entirely in your browser using the File API; nothing is sent to a server.

Are cell formulas included in the output?

No, only their last computed values, since CSV has no concept of formulas, only plain text and numbers.

Excel to CSV Converter - Real .xlsx/.xls Parsing

Overview

Introduction

Getting a CSV out of an Excel workbook usually means opening it in a spreadsheet app and using File > Export, an extra step when all you need is the plain-text table.

This tool skips that: upload the real .xlsx or .xls file directly and get CSV text back, entirely in your browser.

What Is Excel to CSV Converter?

A real file-upload Excel-to-CSV converter, built on SheetJS, the same parsing library used across most JavaScript spreadsheet tooling.

It reads a workbook's actual binary structure and flattens the selected sheet into comma-delimited text, rather than requiring a prior manual export.

How Excel to CSV Converter Works

The uploaded file's bytes are parsed into a SheetJS workbook, which exposes every sheet by name.

The selected sheet is converted with SheetJS's CSV writer, which walks each row's cells left to right, quoting values that contain commas, quotes, or line breaks.

When To Use Excel to CSV Converter

Use it when you have an .xlsx or .xls file and need plain CSV for a script, database import, or another tool that doesn't read Excel formats directly.

It's also useful for quickly checking what a specific sheet's raw table looks like without opening the file in a spreadsheet app.

Often used alongside Excel to JSON Converter, CSV to JSON Converter and JSON to CSV Converter.

Features

Advantages

Reads real Excel binary formats directly, not just files that have already been exported to CSV.
Lets you pick exactly which sheet to export when a workbook has more than one.
Runs entirely client-side, so spreadsheet data never leaves your browser.

Limitations

Only one sheet converts to CSV at a time, since CSV itself can only represent a single flat table.
Capped at 25 MB per file to keep parsing responsive on the main thread.

Excel to CSV vs. exporting from a spreadsheet app

Excel to CSV vs. exporting from a spreadsheet app
Approach	Requires opening a spreadsheet app	Sheet picker	Runs in-browser
This tool	No	Yes	Yes
Manual File > Export	Yes	One sheet visible at a time	No

Examples

Converting a two-row sheet

Input

Sheet1: header row [name, age], data rows [Ada, 30] and [Grace, 40]

Output

name,age
Ada,30
Grace,40

Each row's cells are joined with commas, and rows are separated by newlines.

Best Practices & Notes

Best Practices

Remove merged cells before exporting; SheetJS repeats the merged value into each covered cell rather than preserving the merge.
Check the sheet picker before downloading, especially for workbooks with several similarly-named tabs.
If the destination system expects a different delimiter than a comma, run the output through a delimiter-conversion tool afterward.

Developer Notes

Parsing uses `XLSX.read(bytes, { type: "array" })` and export uses `XLSX.utils.sheet_to_csv(sheet)`, which applies RFC 4180 quoting rules with LF row separators by default.

Excel to CSV Converter Use Cases

Preparing a CSV import file for a database or SaaS tool from an Excel export
Pulling one sheet out of a multi-tab workbook as a flat CSV for a script
Converting legacy .xls reports to CSV without opening them in desktop software

Common Mistakes

Assuming every sheet in a workbook exports at once; only the sheet selected with the buttons above the output converts.
Not re-checking quoting after editing exported CSV by hand, since a stray unescaped comma or quote inside a value will misalign columns downstream.

Tips

If a numeric column reads oddly in the CSV, check that the source cells in Excel are formatted as numbers rather than text before uploading.
Open the downloaded CSV in a plain-text editor once to confirm quoting looks right before feeding it into an automated pipeline.

Excel to CSV Converter