An .stl file is easy to open free, with nothing to install. A free online viewer or your 3D printing slicer shows it in minutes, on Windows or Mac.

A .dxf file is the easy CAD format to open. Free viewers, free editors and laser or CNC software all read it. Here is how, for every use case.

Converting a .step file to .stl for 3D printing? Check if your slicer opens .step files directly first, then use FreeCAD or Fusion for free.

Don’t own SolidWorks or Inventor? You can open a STEP file free online or in FreeCAD, and even edit the 3D geometry. Here’s how.

A NEF file is Nikon’s RAW photo format. Here’s how to view, edit, and convert it for free without any paid software.

A .pages file is made by Apple Pages on Mac or iPhone. On Windows, you cannot open it directly. Here is what to do instead.

An EPUB is a standard ebook format. Open it free on Windows with Calibre or Edge, on Mac and iPhone with Apple Books, and on Android with any reader app.

An ISO file is a disc image, and the right way to open it depends on what you want to do. Mount, extract, burn, or make a bootable USB. Here’s how.

You don’t need Adobe Photoshop to open a PSD file. Free tools let you view, edit, and convert it in minutes, right in your browser or desktop.

A .tmp file is a temporary leftover, not something you open. Learn how to recover unsaved work, delete it safely, or spot what made it.

Windows hides file extensions by default. Here is how to turn them on in Windows 11, Windows 10, and macOS, and why it matters for security.

The right way to open a .rar file depends on your OS, and on Windows, your exact version. Windows 11, Windows 10, and Mac, all covered here.

A .torrent file is a small pointer, not the actual content. Open it in a BitTorrent client like qBittorrent to start downloading. Here is what to know.

A .vob file is a DVD video track. The free VLC player opens it, but for the whole film in order, open the VIDEO_TS folder instead of one file.