Free Online STL Viewer

Open and inspect STL, OBJ and 3MF files right in your browser: rotate, zoom, check the size in millimetres, and estimate the volume and filament weight before you print. 100% free, no sign-up, and your file never leaves your computer.

Drag & drop your 3D file here STL, OBJ or 3MF · processed locally in your browser
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How to view an STL file online

  1. Open the file: drag your STL, OBJ or 3MF file into the box above, or click Choose file.
  2. Inspect the model: left-click and drag to rotate, scroll to zoom, right-click and drag to move. On phones, use one finger to rotate and two fingers to zoom.
  3. Check the details: see the exact width, depth and height in millimetres, the volume, the triangle count, and an estimate of how much filament it will use.
  4. Estimate the cost: click Estimate print cost to send the weight straight into our 3D print cost calculator.

Why use the STLFLEX online STL viewer?

  • Private: files are opened locally in your browser and are never uploaded to any server.
  • Free and unlimited: no account, no watermark, no file limits.
  • Works everywhere: Windows, Mac, Linux, Chromebook, Android and iPhone, with nothing to install.
  • Made for 3D printing: check that a model fits your print bed and how much filament it needs before you slice it.

Frequently asked questions

Is this STL viewer really free?

Yes. The viewer is completely free to use, with no sign-up and no limits on the number of files you open.

Are my files uploaded anywhere?

No. Your file is read directly by your web browser on your own device. Nothing is sent to STLFLEX or any other server.

Which file formats are supported?

You can open STL (binary and ASCII), OBJ and 3MF files, the most common formats for 3D printing. Not sure which one to use? Read our guide STL vs 3MF.

Why does my model look tiny or huge?

STL files don’t store units. Most 3D printing files are in millimetres, but if a model was exported in inches or metres the size will look wrong. Scale it in your slicer by 25.4 (inches) or 1000 (metres).

How accurate is the filament weight estimate?

The solid weight is calculated from the model’s exact volume. The infill estimate is an approximation, because real weight depends on walls, infill and supports. Your slicer gives the exact figure.

Looking for something to print?

Browse our premium STL files, popular flexi toys and money-saving STL packs.