All tools

STL viewer

Open an STL file to turn it round, measure it and check that it is a closed shape for 3D printing, without installing anything. Free, with no account or uploads.

Turn it round, measure it and see whether it is a closed shape. Its numbers are read as millimetres; change that if it looks the wrong size.

Drop an STL file to open it

Or choose one. For an OBJ with its MTL and pictures, or a glTF with its .bin, choose them all at once.

  • GLB
  • STL
  • OBJ
  • FBX
  • STEP
  • 3MF
  • USDZ
  • IFC
  • 3DM
  • +22 more

Stays on your device. Nothing is uploaded.

How it works and help

A little help along the way

Follow these steps. Every option is explained underneath. Everything happens in your browser; the model is never sent anywhere.

  1. Open the modelDrop it on the page or press Choose a file. An OBJ shows its colours when its .mtl file and pictures are chosen with it; a .gltf needs its .bin and pictures too. Choose them all at once.
  2. Turn it roundDrag to turn it, scroll or pinch to zoom, and drag with the right mouse button or two fingers to move it. Fit brings the whole model back into view; Front, Top, Side and Corner look at it from those sides.
  3. Say its size, if it has noneSTL, OBJ and PLY files do not say what their numbers mean. The page reads STL files in millimetres, as 3D printers and CAD programs write them; if the size looks wrong, choose the unit the file was made in.
  4. Choose how fine curves are, for CAD filesSTEP, IGES and BREP files keep exact curves, which are cut into flat triangles to be drawn. Fine suits most parts; Very fine follows curves more closely and makes a larger model, Draft a quicker, coarser one.
  5. Measure itThe size of its box is shown at once, with its surface area, and its volume when it is a closed shape. Press Measure, then two points on the model, for the distance between them; a press near a corner snaps to it.
  6. Look insideCut slices through it across its height, width or depth. Parts lists every piece by name: hide one, or press it to see which it is.
  7. Save a picturePicture saves a PNG of the model as it is shown, at the size set under More options, on a clear background if you like.

Questions people ask

Why is my STL the wrong size?
An STL holds numbers without a unit. The viewer reads them as millimetres, as 3D printers and CAD programs write them. If the model looks a thousand or twenty-five times too big or small, choose metres or inches under Its numbers are in.
How do I know if my STL is ready to print?
The viewer checks every edge. It says A closed shape when each edge joins exactly two faces turned the same way, and gives the volume; otherwise it counts the holes, the edges shared by three faces or more and the faces turned the wrong way.
Is my STL uploaded?
No. It is read and drawn by your browser on your device, and nothing about it is sent anywhere, so there is no size limit but your device's memory.

This page is the 3D viewer, opened for this one job; every other tool it has is one press away. Each of its settings is explained on the 3D viewer's own page.

Read the step-by-step guide

Guides

Same tool, other jobs

Tools nearby