How do I convert XLSX to XLS?

Add your XLSX file to the upload area above, then press Convert. The XLS 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 XLS reduce quality?

Text, structure and images carry over faithfully. Exact page layout does not, because XLS lays content out differently from XLSX. Check headings, tables and page breaks in the result.

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.

SpreadsheetLayout rebuiltRuns in your browser

XLSX to XLS Converter

Turn XLSX files into XLS in a couple of clicks. The modern Microsoft Excel workbook format. Excel's pre-2007 binary workbook. Content is preserved and the layout is rebuilt for the target format.

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 XLS — 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 XLS explained

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

The pre-2007 Excel format is a binary structure limited to 65,536 rows and 256 columns — limits modern datasets routinely exceed.

Where XLSX files come from: Excel, Google Sheets exports and business reporting systems.
Where XLS is used: Spreadsheets from Excel 2003 or earlier, and some legacy export systems.

XLSX vs XLS

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

XLSX compared with XLS
Property	Source	Target
Compression	Lossless	None
Introduced	2007	1987
Browser support	Excel, Google Sheets, Numbers, LibreOffice.	Still opens in Excel and LibreOffice.

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.
XLS is stronger at: Still opens in Excel and LibreOffice.

Why convert XLSX to XLS?

People make this switch when they run into the limits of XLSX: feeding data into a script, database or another system. XLS is the better fit when a legacy system demands it specifically.

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: Hard row and column limits. Larger files than XLSX.

What is preserved when converting XLSX to XLS?

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.

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