XLS to XLSX converter
Upload a XLS, get a polished XLSX back in seconds. StandardsPDF handles the conversion in your browser so your files stay yours.
Convert XLS to XLSX
Drop your files to try StandardsPDF. This tool is available in the full workspace.
Keeps rows, columns and cell values intact
Retains number formats so totals still read correctly
Files auto-deleted from our servers within 60 minutes
Works in any modern browser – desktop, tablet or phone
How it works
Convert XLS to XLSX in 3 steps
Select the XLS you want to convert
Start the conversion – most finish in seconds
Grab your new XLSX, ready to use
Private by default
Files are encrypted in transit and deleted within 60 minutes.
Fast
Most jobs finish in under 10 seconds. No queueing.
No signup on free tier
5 documents per day, no credit card required.
FAQ
Frequently asked questions
How do I convert XLS to XLSX?+
Upload your XLS file (or drag it onto the box above), wait a few seconds while StandardsPDF converts it in your browser, then download the XLSX. There is nothing to install and no account required.
Is converting XLS to XLSX free?+
Yes. XLS to XLSX conversion is free on the StandardsPDF free tier – no watermark, no signup, and no credit card. A Pro tier lifts the file-size and daily limits if you need more.
Will the XLSX keep the quality of my XLS?+
StandardsPDF aims for the highest fidelity the XLSX format allows, so your spreadsheet comes through looking as close to the original as possible. Some format-specific details may adapt where XLSX works differently to XLS.
Are formulas kept when I convert XLS to XLSX?+
Cell values, rows and columns from your XLS are always preserved. Live formulas carry into the XLSX when it supports them, otherwise they become their calculated values.
Can I convert several XLS files to XLSX at once?+
Yes – add multiple XLS files and StandardsPDF processes them as a batch, returning a XLSX for each.
Can I convert XLS to XLSX on my phone?+
Yes – the XLS to XLSX converter is fully responsive and works in Safari, Chrome and other modern browsers on iOS, Android and iPadOS.
How long does a XLS to XLSX conversion take?+
Most XLS files convert to XLSX in a few seconds. Larger or higher-resolution files take a little longer, but there is never a queue on the free tier.
Is my XLS file kept private during XLS to XLSX conversion?+
Yes. Your XLS is processed in an isolated worker, never shared, and permanently deleted from our servers within 60 minutes. Most XLS to XLSX conversions happen right in your browser.