If you work with Excel files, you’ve likely faced format issues. Many older systems and legacy software still require files in .xls format, not the newer .xlsx. This is common in outdated tools used across various industries.

Most spreadsheets today are saved as .xlsx, making an Excel to XLS converter essential. It helps preserve your formulas, formatting, and structure. 

Here, you'll see how to convert files correctly, avoid common errors, and pick the right tool for smooth system compatibility.

Why Convert Files from Excel to XLS?

If you're working across different systems or dealing with older tools, converting XLSX to XLS still matters. Here are few reasons why this format change is often necessary:

Ensure Compatibility with Legacy Software

Older software and systems may not support .xlsx files. Converting your Excel files to .xls ensures they open without problems. It’s the best way to keep your data usable across outdated platforms still common in many workplaces. Especially in industries with strict software policies or limited upgrade options.

Avoid File Opening Errors

Some tools display errors or fail to open .xlsx files properly. When you convert them to .xls, the chances of those errors drop. It’s a safer option when you’re sending files to others who might use old versions of Excel or older spreadsheet-reading applications in daily tasks.

Preserve Data When Sharing

When sharing Excel files, formatting or formulas may break depending on the recipient's software. Converting to .xls helps avoid that. It preserves the layout and formulas, so the other person sees and uses the file as you intended. Without needing to fix or recheck anything after opening it.

Reduce File Size for Faster Processing

.xls files usually take up less space than .xlsx. That means faster upload, download, and loading speeds, especially helpful on slower devices or networks. It’s also easier to send these smaller files over email or store them in shared folders with strict space limits or upload restrictions.

Meet System Upload Requirements

Many business or internal systems only accept files in .xls format. If you upload .xlsx, they might reject it. Converting beforehand ensures smooth uploads. It also saves time, avoiding last-minute file errors during reporting, data imports, or when integrating spreadsheets into older software solutions or database systems.

How to Use an Excel to XLS Converter (Step-by-Step)

If you need to convert Excel files to the older .xls format, don’t worry—it’s easy. Follow these simple steps to get your file ready without losing data or structure:

Choose a Reliable Converter Tool

Start by picking a trusted Excel to XLS converter. You can use offline software or a web-based tool. Make sure it doesn’t limit file size and supports basic formatting and formulas. Read reviews if you're unsure which one to pick. A good tool will keep your file accurate and clean after conversion.

Upload Your Excel File (.xlsx)

Open the converter and upload the Excel file you want to convert. Most tools allow you to drag and drop the file or use a browse button. Make sure you’re uploading the correct version. Once the file is loaded, the tool will prepare it for the format change automatically.

Select XLS as the Output Format

In the conversion settings, choose .xls as your output file type. This tells the tool what format to use when saving your file. Some tools offer multiple format options, so double-check that you’ve selected the correct one before starting the process to avoid creating the wrong type of file.

Review Settings and Start Conversion

Before converting, check any available settings like formula handling or sheet protection. Some tools let you choose what to keep or discard. Once everything looks good, click the convert button. The tool will process the file and prepare your new .xls version while preserving structure and formatting.

Download and Verify the File

After conversion is done, download your new .xls file. Open it in Excel to check everything—formulas, formatting, and content. Make sure nothing is missing or broken. If something looks off, try converting again with different settings or another tool. Always save a backup of the original file before converting.

Best Excel to XLS Converter Free

If you're working with Excel files, choosing the right converter saves time and avoids errors. These tools make Excel to .xls conversion fast, safe, and accurate:

Bank Statement Converter

Bank Statement Converter tool converts Excel files to .xls while preserving structure, format, and privacy. No sign-up, no software, and no tech skills needed. It's fast, browser-based, and ideal for sensitive files, ensuring layout stays perfect and data stays secure.

Microsoft Excel

The built-in “Save As” option in Microsoft Excel lets you convert .xlsx to .xls easily. It’s reliable and keeps most formatting intact. However, it won’t alert you to some function losses, so you should double-check formulas and layouts before sending or uploading your converted file.

Softo 

Softo offers a desktop-based Excel to .xls converter that works well with structured data. It preserves layout, supports batch processing, and keeps your files offline. It's user-friendly and customized to handle data formats without risking privacy or breaking the structure.

CloudConvert

CloudConvert is an online tool that supports many file types, including Excel to .xls. It’s fast and easy to use, but less ideal for sensitive documents since files are uploaded online. If privacy isn’t a concern, it works well for one-time conversions or general Excel documents.

Zamzar

Zamzar offers a clean interface and supports Excel to .xls conversion online. It's easy to use and doesn’t require installation. However, large files may take longer, and some advanced formatting might not carry over. It’s best for small files when quick, casual conversion is needed.

When to Use an Excel to XLS Converter

Not sure when you actually need an Excel to XLS converter? Here are clear situations where using one can help you avoid issues and keep your files working across different tools.

Working with Old Software or Systems

If you use older software that can’t open .xlsx files, you’ll need to convert them to .xls. Many legacy systems still depend on this older format for proper file reading and display. Using a converter avoids errors and lets your files open smoothly without losing structure or content.

Sharing Files with Others Using Older Excel

When you’re sending Excel files to clients or team members who use old versions of Microsoft Excel, they might not be able to open .xlsx files. Converting to .xls ensures your file is accessible to everyone, especially those who haven’t upgraded their software in a long time.

Uploading Files to Legacy Portals

Some portals or data platforms only accept .xls uploads. If you try to upload a .xlsx file, it might get rejected or show an error. Converting it beforehand helps avoid last-minute issues and makes sure your file is accepted on the first try—no back and forth needed.

Automating Data with Older Scripts

If your automation scripts or macros were written years ago, they may not support .xlsx files. These older setups often work best with .xls formats. Converting your Excel file ensures your script runs smoothly without needing updates or changes to the automation process.

Reducing File Size for Easier Transfers

While .xlsx files are generally smaller, in some cases .xls files can be easier to share, especially in older environments. Email clients or upload tools with strict size limits might block .xlsx files. A simple conversion to .xls can help the file go through faster and more reliably.

Common Excel to XLS Conversion Issues & Fixes

Converting from .xlsx to .xls seems simple, but small issues can cause big trouble.  Here's what to look out for and how to fix it:

Formatting Gets Lost After Conversion

Sometimes, numbers, dates, or fonts change after you convert. This happens because .xls doesn’t support all the formatting used in .xlsx. After converting, check totals, and column widths, then reapply the original formatting manually if needed to keep your bank statement readable and accurate.

Some Formulas Stop Working

Advanced Excel formulas like IFERROR or XLOOKUP don’t work in .xls. The older format doesn’t support newer functions. To fix this, use simpler formulas or update your sheet with supported ones like IF, VLOOKUP, or basic math before converting your file.

Compatibility Warnings Appear

When saving as .xls, Excel might show a compatibility warning. Don’t ignore it. It tells you what might break during conversion. Review each warning, then adjust unsupported elements so your file stays clean and error-free in the final .xls version.

File Size Increases After Saving

Converting to .xls can make your file larger. That’s because .xlsx uses compression while .xls doesn’t. If size matters—especially for uploads—try removing empty rows, images, or hidden sheets before converting. This helps reduce the .xls file size without affecting your data.

Macros and Scripts May Not Transfer

Macros in .xlsx might not work correctly in .xls. Some scripts need .xlsm instead. If your bank file uses automation, consider saving it as .xlsm, or recheck the macro settings after converting to make sure nothing’s broken.

Embedded Files or Charts Disappear

If your Excel has charts, images, or embedded files, they may not show up properly in .xls. The older format has limits on what it can display. You’ll need to either simplify your file or reinsert key visuals after converting to make your file clear again.

Conclusion

Converting Excel files to .xls might seem minor, but it can prevent major issues—especially when working with outdated software, legacy systems, or file upload requirements. Choosing the right format helps avoid compatibility errors, broken formulas, or rejected files.

Always use a trusted Excel to XLS converter that preserves layout and data. Check the output to make sure nothing's missing. And if you convert files often, consider automating the process to save time and reduce manual mistakes.