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File converter / Documents / Convert to XLS / XLSX converter / XLS to XLSX

Convert XLS to XLSX

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Choose file to convert to .xlsx
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You can convert XLS file to XLSX as well as to variety of other formats with free online converter.

How to convert xls to xlsx?

How to convert xlsx to xls?
Step 1

Upload xls-file

Select xls file, which you want to convert, from your computer, Google Drive, Dropbox or drag and drop it on the page.
Step 2

Convert xls to xlsx

Select xlsx or any other format, which you want to convert.
Step 3

Download your xlsx-file

Wait till your conversion process will be completed and click download converted xlsx file.

Online and free xls to xlsx converter

Fast and easy
Just drop your xls files on the page to convert xlsx or you can convert it to more than 250 different file formats without registration, giving an email or watermark.
Don't worry about security
We delete uploaded xls files instantly and converted xlsx files after 24 hours. All files transfer with secured an advanced level of SSL encryption.
All in the cloud
You don't need to install any software. All xls to xlsx conversions make in the cloud and don't use any resources of your computer.

Microsoft Excel Binary File Format

File extension .xls
File category documents
Description XLS – is a spreadsheet created by a popular Microsoft Excel application. It includes document data that is located in cells that have a specific address. They can contain formulas, mathematical equations that are associated with information in other cells, and fixed information. It is often used for the development of graphs and charts. The format allows to store and edit a large range of parameters - images, tables, macros, types, diagrams. It has been widely used until the appearance of the 2007 version of Excel, and then it was replaced with the XMLSS extension. The information inside the XLS document is contained in a series of static-size streams, their location is described using several segment distribution tables. It differs in backwards compatibility and supports various file formats created for DOS. It is often used by web browsers to exclude the use of binary formats. The utility is included in the Microsoft office suite and, in addition to Excel, can be opened by various applications like Apache Open Office, Libre Office, adapted to Mac OS, Windows or Linux.
Technical details The relevance of the format is explained by its simplicity, although it does not support separate functions, for example, storing VBA macros. Until XMLSS appeared, the Excel application used the Biff extension when formatting, which was created on the basis of the IFF container format. Due to this, changes to the book templates and their contents were available. After the introduction of the new format in 2007, the program has not lost the backward compatible properties, which guarantees the wide distribution of XLS in the future. Subsequently, the XLS extension was replaced by the XLSM, XLSB and XLSX formats.
Programs
Microsoft Office
LibreOffice
Kingsoft Office
Google Docs
Main program Microsoft Office
Developer Microsoft
MIME type
application/vnd.ms-excel

Office Open XML Document

File extension .xlsx
File category documents
Description XLSX – is an e-book created with one of the versions of the Excel program older than 2007. Thus the data have the form of the tables consisting of columns and lines. Each table is divided into cells that have a unique address, which consists of numeric and alphabetic characters. Cells contain data, both manually entered, and information that was obtained as a result of calculations. The extension allows the use of images, diagrams and graphic information. XLSX files are formatted based on the Open XML standard, which allows you to compress data by the type of ZIP. The archive contains a file for the description of the table and individual files for each of its worksheets. The format makes it possible to develop and edit complex multi-sheet spreadsheets with a variety of formulas and data sources.
Technical details Using the XLSX extension helps to optimize the content of the file, the technology of managing and restoring information. The format significantly increases the capabilities of binary files of obsolete Excel program variants. All applications that display XML can work correctly with the XLSX extension. Due to the preservation of data in XML format, reliable data storage is provided. This allows you to transfer files over local networks seamlessly.
Programs
Microsoft Office
LibreOffice
Kingsoft Office
Google Docs
Main program Microsoft Office
Developer Microsoft
MIME type
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

FAQ

❓ How can I convert xls to xlsx?
Firstly, select a xls file you want to convert or drag and drop it. Secondly, select xlsx or any other format you want to convert your file to. Then click convert and wait until your file is converted
⏳ How long should I wait to convert xls to xlsx?
Documents conversion usually takes a few seconds. You will convert xls to xlsx very quickly.
🛡️ Is it secure to convert xls to xlsx on OnlineConvertFree?
Sure! We delete your uploaded and converted files, so nobody has access to your information. All types of conversion on OnlineConvertFree (including xls to xlsx) is 100% safe.
📱 Can I convert xls to xlsx without software installation?
Absolutely! OnlineConvertFree doesn’t require installation. You can convert any files (including xls to xlsx) online on your computer or mobile.