How do I convert XLSX to CSV?

Add your XLSX file to the upload area above, then press Convert. The CSV file downloads straight to your device. You do not need an account, and there is no watermark.

Are my files uploaded to a server?

No. This conversion runs entirely inside your browser using WebAssembly, so the file never leaves your device — you can even disconnect from the internet after the page loads and it will still work.

Does converting to CSV reduce quality?

Nothing is re-encoded — the content is taken out of the XLSX container as-is, so its quality is unchanged.

How large a file can I convert?

Up to 100 MB per file for this conversion. Because the work happens in your browser, the practical limit is your device's memory — larger files work on a desktop with plenty of RAM and may fail on an older phone.

Can I convert several files at once?

Yes. Add as many as you like and press Convert All. Each file is processed independently, so one failure does not stop the rest, and you can download everything together as a ZIP.

Can I use this on my phone?

Yes. FileTools360 works in mobile browsers on iOS and Android, including choosing files straight from your camera roll. Very large videos may run out of memory on a phone — those are better converted on a laptop.

SpreadsheetExtracted as-isRuns in your browser

XLSX to CSV Converter

Turn XLSX files into CSV in a couple of clicks. The modern Microsoft Excel workbook format. Flat tabular text — one table, no formatting. Content is pulled out of the source container rather than re-authored.

On your deviceNever uploadedGone when you close the tabHow this works

Drop your files here

XLSX files (.xlsx, .xlsm) · up to 100 MB each

or paste files from your clipboard

Ready when you are

Drop a XLSX file above and FileTools360 will turn it into CSV — right here on your device, without uploading anything.

⌘K to search converters

How to use it

1
Add your XLSX files
Drag them onto the upload area, choose them from your device, or paste them from your clipboard. You can queue several at once.
2
Adjust the settings if you want to
The defaults suit most people. Open Advanced to control delimiter and header handling.
3
Convert and download
Press Convert. Everything happens on your own device — nothing is uploaded. Download files one by one, or grab them all as a ZIP.

XLSX and CSV explained

XLSX is Excel's modern format — a ZIP of XML holding cells, formulas, formatting, multiple sheets, charts and pivot tables.

CSV is plain text where each line is a row and commas separate the fields. There is no formatting, no formulas, and no second sheet — which is precisely why every system on earth can read it.

Where XLSX files come from: Excel, Google Sheets exports and business reporting systems.
Where CSV is used: Database exports, analytics tools and data interchange between systems.

XLSX vs CSV

The two formats solve different problems, which is why converting between them involves trade-offs rather than a straight upgrade.

XLSX compared with CSV
Property	Source	Target
Compression	Lossless	None
Introduced	2007	—
Browser support	Excel, Google Sheets, Numbers, LibreOffice.	Every spreadsheet, database and programming language.

XLSX is stronger at: Formulas, formatting, charts and multiple sheets in one file. Compact relative to the old .xls. Supported by Excel, Sheets, Numbers and LibreOffice.
CSV is stronger at: Readable by every spreadsheet, database and programming language. Plain text, so it diffs and streams well. Tiny files.

Why convert XLSX to CSV?

People make this switch when they run into the limits of XLSX: feeding data into a script, database or another system. CSV is the better fit when moving data between systems.

XLSX limitations that prompt the switch: Harder to parse programmatically than CSV. Formula compatibility varies between applications. Can carry macros in the .xlsm variant.
What you give up: Exactly one table — no sheets, formatting or formulas. No type information, so leading zeros and long numbers get mangled.

What is preserved when converting XLSX to CSV?

Both formats store the content without discarding data, so this conversion preserves it exactly. The file size may change because the two formats compress differently, but the content itself is unaffected.

CSV has no notion of data types. A product code like 007 becomes 7 unless the importing tool is told otherwise — which is a property of CSV, not a bug in the converter.

About these formats

Source

Excel Open XML Workbook

The modern Microsoft Excel workbook format.

Extensions: .xlsx, .xlsm
MIME type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Best for: Multi-sheet data · Formulas · Business reporting
Compatibility: Excel, Google Sheets, Numbers, LibreOffice.

Target

Comma-Separated Values

Flat tabular text — one table, no formatting.

Extensions: .csv
MIME type: text/csv
Best for: Data imports and exports · Databases · Scripts
Compatibility: Every spreadsheet, database and programming language.

CSV holds exactly one flat table. Formulas become their computed values, and formatting, charts and multiple sheets are dropped.

Good to know