Convert THMX to PPTX

Source format: THMX

THMX is a Microsoft Office theme file used by PowerPoint and other Office apps to store a presentation’s visual design. It typically contains theme colors, fonts, effects, and sometimes background styling that can be applied consistently across slides. A THMX file is usually not a full presentation; it is a design file that can be applied to a deck.

Target format: PPTX

PPTX is the standard Microsoft PowerPoint presentation format based on Office Open XML. It stores slides, text, images, charts, animations, and theme information in a widely supported package. PPTX is the preferred modern PowerPoint format because it is editable, broadly compatible, and supported by Microsoft PowerPoint, LibreOffice Impress, Google Slides, and many conversion tools.

Converting THMX to PPTX is useful when you want to create a presentation that uses a theme and save it in PowerPoint’s native modern format.

How to perform the conversion

Because THMX is a theme and PPTX is a presentation, the usual workflow is to apply the theme to a presentation and then save that presentation as PPTX. The most reliable desktop tool is Microsoft PowerPoint.

1. Open Microsoft PowerPoint.
2. Create a new presentation or open an existing one.
3. Apply the THMX theme using Design → Themes or Design → Browse for Themes.
4. Check that the slides use the expected colors, fonts, and effects.
5. Save the file as PPTX with File → Save As and choose PowerPoint Presentation (*.pptx).

If you only have a THMX file and no slides, create a new presentation, apply the theme, add at least one slide, and then save it as PPTX. This does not convert the theme into slide content; it creates a PPTX presentation that uses that theme.

Alternative desktop software: LibreOffice Impress may open or apply some PowerPoint themes, but THMX compatibility can vary. If the theme does not import correctly, Microsoft PowerPoint is the safest choice.

Online converters: For THMX to PPTX, online conversion sites are often less useful because THMX is a theme file rather than a complete presentation. If you use an online service, choose a reputable provider and verify that the resulting PPTX preserves the theme correctly. In most cases, desktop PowerPoint is the better option.

Notes on compatibility and limitations

THMX to PPTX is not a direct one-to-one file conversion. A THMX file usually does not contain slide content, so the resulting PPTX may simply be a new presentation with the theme applied. If the theme uses custom fonts or effects, those may not render exactly the same on systems that do not have the same fonts installed.

Some theme elements may not transfer perfectly between Office versions or non-Microsoft apps. For best results, use Microsoft PowerPoint on Windows or macOS, and keep the original THMX file if you need to reuse the theme later. If your goal is to reuse the design, saving the themed presentation as PPTX is the correct workflow.