STL Viewer: 3D Print Files

STL Viewer opens 3D print files on your phone or tablet and shows them in clear, smooth 3D. It is an STL viewer made for makers: check a model's size, volume and filament before you print it, wherever you are and without internet. Your files are read on your device and are never uploaded.

Open models from the file picker, from the share menu, or with "Open with" in your file manager, email or cloud storage app. Models inside a ZIP archive open too.

INCLUDED FOR EVERYONE
• Open STL (binary and ASCII), OBJ with MTL colors, 3MF and PLY files, also from ZIP archives
• Solid, wireframe and x-ray views, a print bed grid and XYZ axes
• One finger rotates, two fingers pan, pinch zooms, double-tap resets the view
• Model info: width × depth × height in mm or inches, triangles, volume, surface area and a closed (watertight) mesh check
• Filament calculator: estimated weight and length for PLA, PETG, ABS or TPU, 1.75 or 2.85 mm, with an infill slider
• Your choice of model color, or the colors saved in the file
• The 10 most recent files with previews, and six original sample models to try right away
• Large files load with progress and a Cancel button
• Dark theme, a tablet layout with a side panel, and screen reader support

PREMIUM ADDS
• Measure: tap two points on the surface to get the distance and the X, Y and Z differences
• Cross-section: cut along X, Y or Z with a solid cut face, plus the section's width, height and area
• Scale & export: scale by percent or to a target size, convert inches to millimeters and save as binary STL
• Compare: open a second model next to the first and compare dimensions, volume and triangles
• Image export: save the current view as a PNG image
• Unlimited recent files and no ads
Premium is a one-time lifetime purchase or a yearly subscription. Without Premium, you can watch a short ad to measure once.

WORKS WITH YOUR SLICER
STL Viewer opens files made for or exported from slicers such as Cura, PrusaSlicer, OrcaSlicer and Bambu Studio. Check the model here, then slice it in the program you already use. G-code files are not supported.

WHO IT IS FOR
• Makers and hobbyists: see whether a downloaded model fits your print bed and how much filament it needs.
• Students: open class projects anywhere and look inside parts with cross-sections.
• Sellers of 3D models: preview files and confirm dimensions and scale before you send or list them.
• Engineers and designers: review parts on the shop floor and compare two versions.

QUESTIONS
Does the STL viewer work offline?
Yes. Viewing, model info and the filament estimate need no internet. A connection is used only for ads and purchases.

Which files can I open?
STL, OBJ (select the MTL file too for colors), 3MF, PLY and ZIP archives that contain one of them. For STEP, glTF and other formats, export the model as STL, OBJ or 3MF first.

Which units are used?
STL, OBJ and PLY files store no unit, so millimeters are assumed; switch a file to inches if it was drawn in inches. 3MF files declare their unit. Sizes are shown in mm or inches, as you prefer.

Why is the filament amount an estimate?
It assumes a 0.8 mm solid shell (about two 0.4 mm lines) and your infill inside. Supports, brims and slicer settings change the real amount.

What about privacy?
No account and no sign-in. STL Viewer processes your models on your device and never uploads them.

All trademarks belong to their owners.

Recent changes:
New: save the current view as a PNG image (Premium). A clearer Premium page that compares what you get with and without Premium. Smaller fixes and improvements.