Thanks for your inquiry. Well, Aspose.Words correctly mimics the way the Microsoft Word’s Html export engine works. To confirm this, please re-save your HTML document to DOC/DOCX format using Microsoft Word. However, for some reasons, the latest version of Aspose.Words (13.5.0) is unable to transform font-size: 11px to 8.5pt (as Microsoft Word does). Instead, it’s currently importing 11px as 8pt. I have logged this issue in our bug tracking system as WORDSNET-8388. Your thread has also been linked to this issue and you will be notified as soon as it is resolved. Sorry for the inconvenience.