OBJ to STL Converter
Convert Wavefront OBJ 3D models to STL for 3D printing — free online. Automatic triangulation of quads and ngons. Geometry-only output ready for any slicer. Up to 100 MB.
Drop your OBJ file hereTap to choose your OBJ file
or
How to Convert OBJ to STL
Upload
Drag and drop your OBJ file into the converter above, or click Choose OBJ File to browse your device.
Convert
Click Convert to STL. Our server triangulates quads and ngons, strips materials and textures, and outputs a binary STL. Takes a few seconds.
Download
Click Download STL to save the converted file. Ready for slicing in Cura, PrusaSlicer, or any other 3D printing software.
Convert OBJ to STL on Any Device
On Windows
Windows users often export OBJ files from Blender, 3ds Max, or Maya and need STL for 3D printing. While these applications can export to STL directly, you may receive OBJ files from other designers or download them from model repositories like Thingiverse or Sketchfab. Our online converter lets you convert OBJ to STL instantly in any browser — Chrome, Firefox, or Edge — without installing additional software or plugins.
On Mac
macOS users working with Cinema 4D, Blender, or SketchUp can convert OBJ files to STL directly from Safari, Chrome, or Firefox. If you have received an OBJ model and need to prepare it for 3D printing on your Prusa, Bambu Lab, or Creality printer, our converter handles the triangulation and format conversion automatically. No need to install MeshLab or open a full 3D application just to change the file format.
On Linux
Linux users running Blender, FreeCAD, or OpenSCAD may need to convert OBJ meshes to STL for slicing. While command-line tools like meshconv or Blender's Python scripting can do this, our online converter is faster for one-off conversions. Works in Firefox, Chrome, or Chromium on any Linux distribution — Ubuntu, Fedora, Arch, or others.
On Mobile
Need to convert an OBJ file on the go? Our converter works on iPhone, iPad, and Android devices. Download an OBJ model from a 3D model library, convert it to STL in your mobile browser, and send it to your 3D printer's web interface or cloud printing service — all without a desktop computer. Useful for quick prototyping workflows when you are away from your workstation.
What is OBJ?
OBJ (Wavefront OBJ) is a universal 3D geometry format originally developed by Wavefront Technologies in the 1980s. It stores 3D mesh data in plain text, making it human-readable and easy to parse. OBJ files define vertices, texture coordinates (UVs), vertex normals, and faces that can be triangles, quads, or ngons (polygons with more than 4 sides).
OBJ supports materials and textures through companion MTL (Material Template Library) files. An OBJ file references its MTL file, which in turn defines surface properties like diffuse color, specular highlights, transparency, and texture map file paths. This makes OBJ a popular interchange format for 3D modeling, animation, and visualization workflows.
The format is supported by virtually every 3D application: Blender, 3ds Max, Maya, Cinema 4D, SketchUp, ZBrush, Rhino, FreeCAD, and many others. Its simplicity and wide support make it one of the most common 3D file formats in use today.
What is STL?
STL (Stereolithography) is a 3D file format created by 3D Systems in 1987 for their stereolithography CAD software. It has become the de facto standard for 3D printing and rapid prototyping. STL files describe the surface geometry of a 3D object using a mesh of triangles — nothing more.
STL is a geometry-only format. It stores triangle vertices and face normals but has no support for materials, textures, colors, UV coordinates, or any other metadata. This simplicity is its strength for 3D printing: slicer software like Cura, PrusaSlicer, Simplify3D, and BambuStudio only need the triangle mesh to generate toolpaths (G-code) for the printer.
STL files come in two variants: ASCII (human-readable but large) and binary (compact and fast to load). Binary STL is the standard for practical use because it produces files 5–10x smaller than ASCII. Both variants contain identical geometric data and are universally supported by all 3D printing software and services.
OBJ vs STL: Quick Comparison
| Feature | OBJ (Wavefront) | STL |
|---|---|---|
| Purpose | General 3D interchange | 3D printing & rapid prototyping |
| Face types | Triangles, quads, ngons | Triangles only |
| Materials & textures | Yes (via .mtl files) | No |
| UV coordinates | Yes | No |
| Vertex normals | Yes (per-vertex) | Per-face only |
| File encoding | Plain text (ASCII) | Binary or ASCII |
| Developer | Wavefront Technologies (1980s) | 3D Systems (1987) |
| File extension | .obj | .stl |
| Colors | Via materials (diffuse, specular) | Not supported |
| 3D printing support | Limited (some slicers accept OBJ) | Universal (all slicers) |
| Best for | 3D modeling, rendering, interchange | 3D printing, CNC, prototyping |
Why Convert OBJ to STL?
3D printing preparation
STL is the industry standard for 3D printing. Slicer software like Cura, PrusaSlicer, Simplify3D, and BambuStudio all require or prefer STL input. If you have designed a model in Blender, 3ds Max, or Maya and exported it as OBJ, converting to STL is the essential step before you can slice and print. Our converter handles the triangulation and format conversion automatically, producing a print-ready STL file.
Simplified mesh for slicing
OBJ files carry materials, textures, UV coordinates, and multiple object groups that slicers cannot use. Converting to STL strips all this unnecessary data and produces a clean triangulated mesh. This eliminates potential parsing errors in slicer software and ensures your model loads correctly every time — no missing faces, no material warnings, just geometry ready for G-code generation.
Universal printer support
Every 3D printer and every slicer application supports STL — it is the universal language of 3D printing. While some modern slicers can import OBJ directly, many still only accept STL. Online 3D printing services like Shapeways, i.materialise, and Sculpteo also prefer or require STL. Converting to STL ensures your model works everywhere, from desktop FDM printers to industrial SLS machines.
Rapid prototyping workflows
When sharing 3D models for rapid prototyping, STL is the safest choice. Model repositories like Thingiverse, Printables, and MyMiniFactory predominantly use STL. If you have a model in OBJ format and want to share it for 3D printing, converting to STL ensures maximum compatibility. Recipients can open the file in any slicer without needing the original 3D application or the accompanying MTL and texture files.