Convert XLS to XLSX Online

CONVERT XLS to XLSX ONLINE

1) Upload XLS file to convert

Drop files here, or Click to select

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Allowed file types: fasta, qif, ofx, iif, srt, ics, excel, ris, bib, ods, xls, xlsx, xlsm, csv, tsv, tab, xlsb, xltx, xlr, pxl, qpw, wb3, wq1, dbf, wk3, 123, mdb, evtx, pages, numbers, sqlite

2) Set converting XLS to XLSX options

3) Get converted file

DOWNLOAD CONVERTED FILE

Full version

Get Total Excel Converter to convert XLS, XLSX, ODT, XLSM, etc. safely.

Convert Excel Files in Batch!;
Convert XLS to XLSX and in many other formats
Convert hundreds of spreadsheets in 3 clicks;
Both MS Office and OpenOffice files;
Have a desktop converter that works without Internet;
Keep your files safe, don't send them to the web;
Get more accurate results with the more poweful engine.

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Total Excel Converter

Total Excel Converter supports almost all Excel extensions: XLS, XLSX, XLSM, XLSB, XLT, XLTM, XLTX, XLK, XLW. When the new Office is released, we will add new file types too.

With Total Excel Converter you can convert Excel to PDF and add a digital signature in one go.

Total Excel Converter can convert each page of your spreadsheet into a separate file.

Tell Total Excel Converter to copy original time stamps if you don't want to change the date.

Have an outdated Microsoft Office 2003? Update all your old files to the new format in one go. Convert XLS files to XLSX in batches.

Total Excel Converter will help you to convert Excel 2003 XML Files (rare option!)

Total Excel Converter has a built-in renamer to give your files new descriptive names. Include a counter, a date or worksheet name into the file name and your files will be in perfect order.

Convert Excel spread sheets via our most straightforward interface.

The widest list of output file types: DOC, PDF, HTML, MHT, XHTML, CSV, TXT, TIFF, JPEG, SVG, RTF, XML, XLS, XLSX, ODS, ODT, Lotus, DIFF, SYLK, LATEX, SQL, DBF, Access!

Total Excel Converter can combine several Excel spread sheets into one TIFF or PDF file.

Want to quickly find a file? Total Excel Converter helps you to preview any document you select.

Add your logo or any other image to the header or the footer of the output file.

Want more order? Add page counters or a date to every page of the output files. Sequential numbering of several folders is avaialble.

Total Excel Converter can copy original time stamps if you want to keep them.

When you convert Excel to PDF you can set user permissions, password-protect your files or sign with a digital signature. Get PDF, PDF/A and non-searchable PDFs.

Total Excel Converter can be run via command line (get the ready-to-use command line from GUI).

How to convert XLS to XLSX?

💾 Upload Your File: Go to the site, click on «Upload File,» and select your XLS file.

✍️ Set Conversion Options: Choose XLSX as the output format and adjust any additional options if needed.

Convert and Download: Click 👉«Download Converted File»👈 to get your XLSX file.

Cloud Based

There is no need to install any software to convert XLS to XLSX with CoolUtils. Simply access the internet, and you can easily convert your file online with our service.

Secure

Our hardware operates in top-tier, highly secure data centers equipped with advanced electronic surveillance and multi-factor access control systems.

Ease of Use

Converting legacy XLS spreadsheets to modern XLSX online has never been so simple. Drop your .xls file and the converter writes a standards-compliant .xlsx that opens in Excel 2007+, Google Sheets, and LibreOffice Calc. Formulas, cell formatting, named ranges, and multiple sheets are all preserved.

Privacy

We understand the importance of privacy, which is why we've developed a comprehensive privacy policy detailing how we handle your files and personal information. You can read the policy here.

XLS File

File extension	.XLS
Category	Document File
Description	XLS is the most popular format for storing table data. It is native Microsoft Excel format with data stored in numbered cells that form columns and rows. The top line and left column of each table contains numbering of each cell that can contain either static or dynamic data that is calculated from formulas. XLS features powerful calculation and charts-building options, as well as rich text formatting. XLS is compatible with numerous table editors such as Calc, PlanMaker, OpenOffice, etc.
Associated programs	Microsoft Excel Microsoft Excel Viewer OpenOffice
Developed by	Microsoft
MIME type	application/vnd.ms-excel
Useful links	More detailed information on XLS files
Conversion type	XLS to XLSX

XLSX File

File extension	.XLSX, .EXCEL
Category	Document File
Description	XLSX is a format from Office Open XML family, a native MS Excel file type starting from version 2007. As opposite to XLS, this format uses ZIP compression that makes XLSX files smaller in size. Actually XLSX file is an archive of XML-documents. The cells in XLSX table can contain plain text, formulas or graphic elements. XLSX can be read in MS Office 2007 and later, Universal Viewer, OpenOffice, MS Office Excel Viewer, Corel WordPerfect Office. This format doesn’t support macros.
Associated programs	Microsoft Excel 2007 OpenOffice OxygenOffice Progessional (Linux)
Developed by	Microsoft
MIME type
Useful links	More detailed information on XLSX files

Rating XLS to XLSX

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XLS to XLSX Conversion — Frequently Asked Questions ▼

What is the difference between XLS and XLSX?

XLS is the binary spreadsheet format used by Excel 97–2003. XLSX is the XML-based Open Office format introduced with Excel 2007 (Office Open XML, ISO 29500). XLSX files are zip archives containing XML files — they are smaller, more transparent, less prone to corruption, and supported by every modern spreadsheet application including Google Sheets, LibreOffice Calc, and Apple Numbers.

Why should I convert XLS to XLSX?

XLS is a legacy format. Excel 2007 and later can open XLS but saves in XLSX by default. Google Sheets and newer applications work better with XLSX. XLSX supports more rows (1,048,576 vs XLS's 65,536), more columns, richer formatting, and better compatibility with Power Query and modern Excel features. Many corporate IT policies now require XLSX for document submissions.

Will formulas work correctly after converting XLS to XLSX?

Yes — formula syntax is identical between XLS and XLSX. All Excel functions, cell references, named ranges, array formulas, and data validation rules are preserved. The values calculated by formulas are preserved as well. You may want to recalculate after opening in Excel to confirm, but conversion does not alter formula logic.

Does the converter preserve cell formatting and colors?

Yes. Font types, sizes, bold/italic/underline, cell background colors, number formats, border styles, column widths, row heights, merged cells, and conditional formatting rules are all preserved in the XLSX output.

Can I convert multiple sheets in a single XLS file?

Yes. All sheets within the XLS file are converted and included in the XLSX output. Each sheet keeps its name, column/row structure, and formatting.

What version of Excel is needed to open XLSX files?

Excel 2007 or later is required. If you are on Excel 2003, install the Microsoft Office Compatibility Pack (a free Microsoft download) to open XLSX files. Google Sheets, LibreOffice, and Apache OpenOffice can open XLSX without any additional software.

Are there file size limits for online XLS to XLSX conversion?

The online converter handles files up to 50 MB. For large spreadsheets or batch conversion of many XLS files at once, the desktop Total Excel Converter has no size or file count limits and supports command-line automation.

Convert XLS to XLSX with Ease

Our online conversion tool provides a seamless experience for transforming your Excel files from XLS to XLSX format. As technology evolves, the need to streamline data management and enhance compatibility across devices becomes paramount. This tool is designed to meet those needs by effectively converting older Excel files into the modern, more versatile XLSX format.

The benefits of converting to XLSX are numerous. The XLSX format, introduced by Microsoft with Excel 2007, offers greater efficiency in file storage and data processing. It supports a wider range of features, including enhanced data recovery options, improved data integrity, and greater compatibility with contemporary software, making it the preferred choice for businesses and individuals alike.

Our conversion tool operates online, eliminating the need for software installation. Simply upload your XLS file, and the conversion process will be executed swiftly, preserving the original formatting and data content. This ensures that the transition to XLSX retains the accuracy and functionality of your spreadsheets.

What sets our tool apart is its focus on user convenience and data security. We prioritize user privacy by using secure file transfer protocols and ensuring that your files are automatically deleted from our servers after conversion. Additionally, our intuitive interface simplifies the process, making it accessible even to users with limited technical expertise.

Whether you are working on individual projects or managing large data sets, this conversion tool provides a reliable solution for modernizing your Excel files. Experience the efficiency and adaptability of XLSX with our straightforward online tool.

Feature	Online Converters	CoolUtils Desktop	Excel Built-in	Other Software
Batch Conversion	Limited	✅ Unlimited	Manual only	Limited
File Size Limit	1-5MB	✅ No limits	System dependent	Varies
Privacy & Security	Upload required	✅ 100% offline	✅ Local only	Varies
Conversion Speed	Internet dependent	✅ Fast local processing	Slow	Medium
Advanced Options	Basic	✅ Full customization	Limited	Basic
Cost	Free/Premium	One-time purchase	Requires Office	Subscription
Formatting Preservation	Good	✅ Excellent	Good	Varies
Multiple Formats Support	Limited	✅ 40+ formats	Few formats	Limited

Convert XLS to XLSX Online