As of 2007, Excel has been saving spreadsheets in the XLSX format by default. Older versions of the popular software published before 2007 only use the XLS format. The XLSX spreadsheets tend to be smaller in size than their XLS counterparts – even if they contain the same content. While newer versions of Excel are still able to open old XLS files, you may run into problems if you try it the other way around. If you’re looking to convert XLSX to XLS, there are some simple tricks you can use. Here, you’ll find two ways to quickly and easily convert XLSX to XLS.

Option 1: Convert XLSX to XLS directly in Excel

If you have a spreadsheet program on your computer that can open XLSX files (i.e. any version since Excel 2007), the easiest way to convert XLSX to XLS is to use the “Save as” function. To do so, follow the steps below:

  1. Open the XLSX file you want to convert.
  2. In Microsoft Excel, go to the File tab located at the top left. For other programs or Mac computers, it is often the first tab in the navigation bar called “Home” or “Start”.
  3. Click on the “Save as” option and select “Excel 97-2003 Workbook (*.xls)” from the drop-down menu.
  4. Select the folder where you wish to save the file and confirm by clicking the “Save” button.

Option 2: Convert XLSX to XLS with an external converter

If you do not have a newer version of Excel, you can use a converter instead. Many of these tools are available online for free. You don’t need to download or install any additional software. The files are converted directly on the provider’s website. Usually, you will see an “Upload file” or “Select file” button on the website. By clicking on this button, the File Explorer will open. From here you can select the file to be converted and upload it by clicking “Open”. Once you have converted the file to XLS format using the converter, you can download it from the website and save it on your hard drive. There are many different converters to convert XLSX to XLS. Below are three options described in detail.

Tool name Important functions Price Operating system
Convertio - available via browser- fast and efficient- possible to upload from Dropbox, Google Drive and a URL- converts all common image, document, presentation, and e-book formats- SSL encryption- no activity tracking through social networks- 100 MB maximum file size- file remains on the servers for 24 hours and can be retrieved during this time free All, because it’s a web application
Aconvert - converts XLSX to XLS, PDF, ODS, CSV, HTML, PNG, JPG, etc.- simple to use- allows for batch conversion free All, because it’s a web application
Zamzar - SSL encryption- enables upload by using drag and drop or by inputting a URL (selecting a link)- converts XLSX to XLS, CSV, DOC, MDB, NUMBERS, NUMBERS09, ODS, RTF, PDF, TXT, TIFF, JPG, PNG, GIF, BMP, HTML, HTML4, HTML5 and XML- can send converted files by email- file remains on the servers for 24 hours- 150 MB maximum file size free All, because it’s a web application

Alternatively, you can also convert an old XLS file into the new XLSX format. Opening the XLXS file is then no longer a problem. However, you need to be careful about changing file extensions yourself. Important information may be lost. Therefore, you should only use the two methods described above to convert XLSX to XLS.

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