Free STL viewer
View and measure STL files

Open an STL file in your browser and check it before you print or send it for a quote: size, volume, weight and whether the mesh is watertight.

Nothing is uploaded: the file is opened on your own computer.

Free, no sign-up. Your file stays on your computer. It is opened in this browser tab and is never uploaded to us or anyone else.

File will not convert, or the model needs cleaning up? Our team fixes and converts it for you. Send us the file and we reply with a fixed price. Send the file

  • Size, volume and solid PLA weight at a glance
  • Measure between 2 points on the model
  • Watertight check before you print
How it works

How to view an STL file online

3 steps, and the file never leaves your computer.

1. Open the STL file

Drop the .stl file on the viewer or click to choose it. Both binary and ASCII STL files open, and so do 3MF files from a slicer.

2. Turn it and zoom in

Drag to orbit, scroll to zoom and use Full screen for a closer look. Edges shows the outline of every sharp corner, which makes small details easier to read.

3. Read the numbers

Under the model you get the size, the triangle count, the volume, the weight in PLA and whether the mesh is watertight. Measure any distance with 2 clicks.

What you see

The numbers the STL viewer gives you

What you need to know before you print a model or ask for a quote.

Size

The width, depth and height of the model. STL files carry no units, and almost all of them are drawn in millimetres, so the numbers are read as millimetres.

Volume and PLA weight

The volume of the closed solid in cubic centimetres, and its weight printed solid in PLA (1.24 g per cm³). A normal print with 15 to 20% infill uses much less, so treat it as the upper limit.

Watertight or not

A model with holes or loose edges cannot be sliced reliably. The viewer checks every edge and says Yes or No, for models up to 400,000 triangles.

Parts

A 3MF or OBJ with several bodies lists each one in the side panel, where it can be hidden to see inside, or clicked to get its own size.

When the file is not enough

What we do with STL files

A scan or a downloaded STL is a mesh of triangles. When you need a clean, editable model or images of the product, that is our work.

Untextured clay model of a terrace of houses with its parking and planting, Finland

3D modeling

Accurate, editable models rebuilt from meshes, scans, drawings or photos, with real dimensions.

See 3D modeling
3D product rendering of a tambour-front storage cabinet shown in black and white finish options side by side on a plain background

3D product rendering

Photoreal product images for web shops and catalogues, from your CAD or mesh files.

See product rendering
3D exterior rendering of a curved hotel and its forecourt at dusk, Estonia

Architectural visualization

Images of buildings before they are built, including printed scale models turned into renders.

See architectural visualization
STL viewer FAQ

Questions about viewing STL files

Opening STL files, weight estimates and what the viewer can do.

Ask us a question
How do I open an STL file without installing software?
Drop it on the viewer on this page. It opens in any current browser on Windows, Mac, Linux, iPhone or Android, and nothing needs to be installed or uploaded.
How is the weight worked out?
The viewer measures the volume of the closed mesh and multiplies it by 1.24 grams per cubic centimetre, the density of PLA. That is the weight of a solid print. With the usual 15 to 20% infill, the real print is much lighter; your slicer gives the exact figure for your settings.
Why does the volume not show for my file?
Volume is only shown for a watertight model, because a mesh with holes has no inside to measure. Close the holes in your slicer, in Microsoft 3D Builder or in Blender, then open the file here again.
Can I edit or fix the STL here?
No. The viewer shows and measures the model and can save a copy as STEP, OBJ, GLB or PLY. To repair holes use your slicer or Blender, and for a model that needs rebuilding, see 3D modeling.
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