Best 4 Tools to Convert XLS to XLSX Online Quickly and Safely

"I have a batch of files that are uploaded to MS Teams (SharePoint Online) every morning in an .xls format. We need to convert them to .xlsx in order to connect via Power BI. I've searched through Flow templates and online forums but I can't find anything. How would I do this?"

Many people face this challenge, especially when older files don’t work seamlessly with modern software. Also, some have many XLS files that need batch processing.

The good news is that you don’t have to waste time searching for complex solutions. Using XLS to XLSX converters online might be your solution. Here are some of the best free online converters you can use to convert your files fast in just a few clicks.

Part 1: Advantages and Disadvantages of Online XLS to XLSX Converters

Using online converters to change XLS files to XLSX can be a quick and easy solution. However, it’s important to know both the benefits and limitations of these tools before you start. Here’s a breakdown of what to expect.

Advantages

• Accessible from any device with an internet connection.
• No need to download or install software, saving time and storage.
• Free to use, which is cost-effective for occasional file conversions.
• Convenient for quick tasks without cluttering your computer.

Disadvantages

• Requires a stable internet connection; slow or unstable connections can delay the process.
• Privacy concerns when uploading files, as there’s a risk of data exposure.
• Free converters may show ads or limit the number of conversions.
• May not support advanced formatting or handle large file sizes, leading to incomplete conversions.

Part 2: How to Choose a Safe Online XLS to XLSX Converter?

Finding a safe online converter for your XLS to XLSX files is important to make sure your data is safe. It also ensures smooth conversions. With so many online tools available, it can be tricky to know which one to trust. To help you choose the right one, here are some key factors to consider before you upload your files.

1. Check Reviews and Ratings: Find tools that have positive reviews with high ratings. This can indicate that the converter is reliable and has been used successfully by others.
2. Ensure Website Security: Make sure the converter uses HTTPS. This secure protocol helps protect your files from unauthorized access during upload and download.
3. Consider File Size Limits: Some converters have restrictions on file size. If you need to convert large XLS files, choose a tool that supports bigger file uploads.
4. No Account Required: Opt for converters that don’t ask you to create an account or sign in. This saves time and helps keep your personal information private.
5. Automatic File Deletion: Choose a converter that automatically deletes your uploaded files after conversion. This ensures your data is not stored on the server longer than necessary.
6. User-Friendly Interface: A beginner-friendly interface makes the conversion process quicker and reduces the chance of errors.

By keeping these factors in mind, you can safely convert your XLS files to the XLSX format without worrying about security risks or data loss.

You may also interest: How to Repair Corrupt Excel XLS/XLSX Files?

Part 3: 4 Reliable Free Online XLS to XLSX Converters

Choosing the right online converter is important to ensure your files stay safe and the conversion works smoothly. Earlier, we discussed how to pick a secure and efficient tool. Now, we’ve done the work for you and selected four trusted converters that meet these standards:

XLS to XLSX Converter Online 1. Zamzar

Zamzar is a user-friendly online converter that supports various file formats, including converting XLS files to XLSX. It focuses on simplicity, allowing you to drag and drop your file, select the desired format, and convert it in just a few clicks.

Zamzar also offers email notifications when your conversion is complete, which can be helpful if you are multitasking. It’s a reliable option, especially for quick and straightforward conversions.

Pros

✅Easy to use with drag-and-drop functionality.

✅Supports multiple file formats, making it versatile.

✅Has email notifications that let you focus on other tasks while waiting for the conversion.

Cons

❌Has limited free usage unless you subscribe.

❌Larger files may take longer to process to convert on Zamzar.

Step 1: Visit Zamzar XLS to XLSX converter website.

Step 2: Click on Choose Files and select your XLS files. Set the output format to xlsx and click on Convert Now.

Step 3: Wait for the conversion, then click Download to get your XLSX files.

XLS to XLSX Converter Online 2. FreeConvert

FreeConvert is a versatile online tool that offers free conversion for different file types, including spreadsheets. The platform ensures fast conversions while keeping the original file quality intact.

One standout feature of FreeConvert is its ability to handle larger files, which is perfect if you’re dealing with big spreadsheets. Additionally, it uses SSL encryption to protect your files during upload and download, enhancing your data security.

Pros

✅Handles large files with ease, perfect for big spreadsheets.

✅Uses SSL encryption for secure file uploads and downloads.

✅Has high-quality conversions that maintain original file accuracy.

Cons

❌It’s free version may include ads.

❌Has daily usage limits for free accounts.

Step 1: Go to FreeConvert XLS to XLSX converter.

Step 2: Click Choose Files to upload your XLS files. Do not worry if your files have a big size.

Step 3: Make sure the output format is set to XLSX and hit the Convert button.

Step 4: After conversion, click Download to save the converted files.

XLS to XLSX Converter Online 3. Convertio

Convertio is another popular online converter known for its ease of use and wide file support. Converting XLS to XLSX with Convertio is straightforward. Convertio allows you to upload files from various sources like Google Drive, Dropbox, or even by URL. It also automatically deletes files from its servers after a short period, making it a safe choice for sensitive documents.

Pros

✅Has an excellent Trustpilot rating for reliability and satisfaction.

✅Its upload options include Google Drive, Dropbox, and URL for flexibility.

✅Deletes files after conversion, ensuring privacy and security.

Cons

❌Its free tier limits file size and daily usage.

❌Has a slower conversion speeds for larger files.

Step 1: Visit Convertio’s XLS to XLSX converter on your web.

Step 2: Click Choose Files to upload your XLS files from your device, Google Drive, Dropbox, or by pasting a URL and then, select XLSX as the output format.

Step 3: Click Convert. Once done, Download your new XLSX files.

XLS to XLSX Converter Online 4. CloudConvert

CloudConvert is a flexible online converter that supports many file types, including XLS to XLSX conversions. It’s known for its high-quality conversions without losing data or formatting. You can easily upload your file, choose the output format, and convert it within seconds.

It also provides a secure environment since all uploaded files are deleted after conversion. Additionally, CloudConvert offers an API for developers who need to integrate file conversion into their own applications.

Pros

✅Supports a wide range of file formats, ideal for various needs.

✅Has high-quality conversions that retain data and formatting.

✅Offers API integration for developers.

Cons

❌Has a lower Trustpilot rating compared to other options.

❌It has limited free conversions unless you upgrade to a paid plan.

Step 1: Go to CloudConvert XLSX converter online.

Step 2: Click on Select File and upload your XLS files from your computer, Google Drive, Dropbox, or URL.

Step 3: Ensure the output format is set to XLSX and click the Convert button. Once the conversion is complete, click Download to save your XLSX files.

Part 4: How to Resolve Failed Online XLS to XLSX Conversion?

Sometimes, online conversions might not go as planned. You might get errors like "conversion failed" or "file format not supported." These problems can happen for several reasons. One common issue is a corrupted XLS file, which online converters can’t process.

In other cases, the file might be too large, or the internet connection might be too slow, causing the process to fail. Sometimes, online converters may not fully support older file formats, leading to incomplete or broken conversions.

To fix such issues, you can use a tool like Repairit File Repair. This software is designed to fix damaged files, including Excel spreadsheets. It can repair corrupted XLS files so you can convert them successfully afterward. With Repairit, you just need to upload the broken file, and the tool will automatically detect and fix issues.

The best part is that it supports batch repairs, so you can fix multiple files at once. Plus, Repairit is easy to use with a simple interface, making it suitable for both beginners and advanced users.

Here is how you can solve this problem using Repairit File Repair:

Step 1. Open Repairit on your computer and go to More Types Repair. Select File Repair.

Step 2. Click +Add and select the corrupted XLS file you want to fix.

Step 3. Click Repair and the software will analyze the file and fix any corruption automatically.

Step 4. Once the repair is complete, you can preview the file to ensure everything is fixed correctly. Click Save and choose a location on your computer to save the repaired file.

Now, you can upload this fixed file to an online converter and convert it to XLSX without issues.

More related topics:
1. How to Repair XLSX File Effortlessly
2. Top 4 Methods to Fix Xlsx Files Online

Conclusion

Converting XLS to XLSX online is an excellent way to access additional features and ensure better compatibility with updated software. By using online converters, you can quickly change your file format without needing to download any extra tools.

However, it's important to choose a reliable and secure converter to protect your data. If you run into any problems during conversion, tools like Repairit can help you fix file issues and get the job done.