What happens when you convert XLS to XLSX
- Every sheet is carried over with its cell values and formulas. The converter rebuilds the workbook from its cells, so charts, images, pivot tables and cell styling such as colours and fonts are not kept.
- The file is read by SheetJS running in your browser; nothing is uploaded.
How to convert XLS to XLSX online
- Press "Choose XLS files" and select one or more files, or drag them onto the box. You can add files of any size your device can hold in memory.
- There are no settings to choose: the converter keeps everything the target format can hold.
- Press "Convert to XLSX". The spreadsheet library, about 900 KB, loads the first time and then workbooks convert in a moment.
- Save each XLSX with its download button. Close the tab and every trace of the files is gone from memory.
Why convert XLS to XLSX?
XLS files usually come from older Excel files and systems that still export the legacy format. People convert them to XLSX because XLSX is what Excel, Google Sheets and most business tools expect, and it keeps every sheet and formula.
In short, XLS is good at what it was made for, and XLSX is the more practical choice when the file has to open, upload or print somewhere else. XLS opens in Excel, Google Sheets, Numbers and LibreOffice Calc, while XLSX opens in Excel, Google Sheets, Numbers and LibreOffice Calc.
How to convert XLS to XLSX on Windows, Mac, iPhone and Android
On Windows
Open this page in Chrome, Edge or Firefox, drag your XLS files in from File Explorer, and press Convert. Each XLSX is saved to your Downloads folder.
On a Mac
Safari, Chrome and Firefox all work. Drag the XLS files from Finder onto the drop zone and the XLSX files land in Downloads.
On iPhone and iPad
Open the page in Safari and tap Choose XLS files. You can pick from Photos or from the Files app. The converted XLSX appears in Files, in the Downloads folder.
On Android
Open the page in Chrome, tap Choose XLS files and pick them from Files or your gallery. The XLSX is saved to the Download folder, where any file manager can find it.
Best settings for XLS to XLSX
There are no settings to choose: the XLS is read cell by cell and written as an Excel workbook with every sheet and its values and formulas.
Check the result in your spreadsheet program before deleting the original: formulas are carried over, but charts, images and styling are not, so a heavily formatted report will look plainer.
XLS vs XLSX: the differences
| XLS | XLSX | |
|---|---|---|
| Full name | Excel 97 to 2003 workbook | Excel workbook |
| Type | spreadsheet | spreadsheet |
| Created by | Microsoft | Microsoft |
| First released | 1997 | 2007 |
| Compression | Lossless | Lossless |
| What it holds | several sheets with values, formulas and formatting in a binary file | several sheets with values, formulas, formatting and charts |
| In a browser | opens in Excel, Google Sheets, Numbers and LibreOffice Calc | opens in Excel, Google Sheets, Numbers and LibreOffice Calc |
| Common uses | older Excel files and systems that still export the legacy format | business spreadsheets, reports and anything shared with Excel users |
| MIME type | application/vnd.ms-excel | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet |
About XLS and XLSX files
What is an XLS file?
XLS is the binary Excel format used before 2007. It is limited to 65,536 rows and 256 columns per sheet, far fewer than XLSX allows.
What is an XLSX file?
XLSX has been the default Excel format since Office 2007. Inside it is a ZIP archive of XML files, one per sheet, plus styles and shared text.
XLS to XLSX not working? Common problems
- The file will not open. Password-protected workbooks are encrypted, so they cannot be read without the password; remove the password in Excel first.
- Dates look like numbers. Spreadsheets store dates as numbers underneath; apply a date format to the column in your spreadsheet program.
- Special characters look wrong in Excel. The CSV is UTF-8; in older Excel, use Data, From Text/CSV and choose UTF-8 instead of double-clicking the file.
Convert XLS to XLSX from the command line
LibreOffice converts spreadsheets from the command line without opening a window:
soffice --headless --convert-to xlsx input.xlsThe converter on this page does the same job in your browser, without installing anything.
XLS to XLSX converter FAQ
Will I lose quality converting XLS to XLSX?
Cell values and formulas are kept exactly. Charts, images and cell styling are not.
Why is the XLSX a different size from the XLS?
Workbook formats differ in how they compress, so the XLSX may be a little larger or smaller than the XLS.
Are my XLS files uploaded anywhere?
No. The conversion runs inside this browser tab using the open-source SheetJS library, so your files stay on your device. You can disconnect from the internet after the page and converter engine have loaded and it still works.
Can I convert several XLS files to XLSX at once?
Yes. Select or drop as many files as you like; they are converted one after another and each gets its own download button.
How do I open an XLSX file?
XLSX opens in Excel, Google Sheets, Numbers and LibreOffice Calc. XLSX is common for business spreadsheets, reports and anything shared with Excel users.
Is this XLS to XLSX converter free?
Yes. There is no sign-up, no watermark and no limit on how many files you convert. The site is paid for by advertising, and because conversions run on your device there is no server cost per file.
Can I convert XLS to XLSX on my phone?
Yes. The converter works in Safari on iPhone and iPad and in Chrome on Android. Converted files are saved to the Downloads folder.