Free Online STL to OBJ Converter

You can use our STL to OBJ conversion tool to quickly and easily convert your 3D model files for free. You may upload up to 20 files at one time, and our batch STL to OBJ converter will process each 3D model and present you with a download link for each file once completed.

Select File(s)

Or drag and drop your files here to upload.
A maximum of 20 files can be uploaded at once.

Please note: Your STL file, once uploaded to our server, will be deleted 15 minutes after upload, so please download your converted STL file before this time.

Our 3D model STL to OBJ tool will load your STL file and, where supported, attempt to extract all the relevant 3D features, such as geometry, textures, and animations. To access the 3D conversion configuration options, click the button when you have selected your files. The current options support the ability to voxelize your 3D model and more.

How to Convert your STL to OBJ Online?

Here are two simple steps to convert your STL to OBJ using our fast and free STL converter tool.

Upload your STL file

Click the "Upload a STL File" button, then select a STL to upload. The maximum file size is 100MB.

Download your OBJ

Click the download link to receive your OBJ file.

Frequently Asked Questions

How can I convert my STL file to OBJ?

First, click the "Upload..." button and select your STL file to upload. Your STL file will be uploaded to our servers. When the STL to OBJ conversion has completed, you can download your OBJ file right away.

How long does it take to convert my STL to OBJ?

We aim to process all STL to OBJ conversions as quickly as possible; this usually takes around 5 seconds; however, this can be longer for certain files, so please be patient.

How accurate is the STL to OBJ conversion?

We aim to provide the best conversion experience. Our tools are under constant review and development, with new features being added every week.

Comparing STL and OBJ Files

The STL and OBJ file formats are both capable of representing a 3D model, but their capabilities and suitability for specific tasks vary. Here we take a closer look at both formats, see what the fundamental differences are, and try to determine which is better suited to a particular task.

Features

In terms of features, the OBJ file format is capable of storing materials, i.e., surface rendering properties, in a separate MTL (short for material) file. This MTL file can also contain references to external texture files when dealing with textured surfaces. External texture files will tend to be either PNG or JPG files; however, there may be other formats used, such as TGA. STL files, on the other hand, have no support for object materials or textures, making the OBJ format the clear winner here if you need to store materials or textures with your 3D model.

The OBJ format also stores its geometry differently from the STL format. Whereas the STL format is a simple list of triangles, the OBJ format makes use of indexed lists of vertices, normals, and texture coordinates, which helps in the reuse of data and reduces the file size compared to the same model in the STL format.

A gingerbread 3D model with no materials stored in the STL format

A fully textured OBJ gingerbread house file

The OBJ formatted gingerbread house normal map

Uses

Due to their ability to contain materials and textures, OBJ files are generally used for storing models where colours and textures are present and for transferring 3D objects between applications. STL files can also be used as a medium for the exchange of simple 3D mesh data if that is all that is needed to be transferred. STL files really come into their own when it comes to 3D printing. Many 3D printing slicer software support the STL format, making it the better format for storing 3D objects you intend to send to a 3D printer.

Summary

Both STL and OBJ formats are popular and have been around for a long time, meaning they both command support amongst 3D modelling applications. Choosing between them depends on the task at hand. If you are intending to 3D print your model, then STL is the most suitable format; for anything else, the OBJ format is likely the best choice.

File format information for STL and OBJ

Extension	STL
Full Name	Standard Triangle Language
Type	3D Model
Mime Type	application/vnd.ms-pki.stl
Format	Text
Opens With	Blender, MeshLab, CAD Assistant, DAZ Studio

The STL, or Standard Triangle Language, file format has been around since the '80s and is supported by most modern 3D modelling applications. In particular, the STL format has become something of a standard format within the area of 3D printing, despite the rise of more modern formats such as 3MF.

STL files come in two flavours: binary or text format. The text format is human-readable, making it easy to perform manual edits, but can lead to very large file sizes. As you can imagine, the binary format is much more compact and represents the majority of the STL files you are likely to encounter.

The format itself is very simple; the 3D model is represented by a sequential list of triangles, with each triangle defined with 3 points consisting of their X, Y, and Z positions, along with an additional vector that contains the face normal (the direction the face is pointing). There is an additional attribute block for each triangle; however, this is largely unused and thus unsupported.

STL Converter Capabilities

When converting 3D model or mesh files using our STL converter, we will attempt to convert colour materials into a suitable format for use in the converted file.

Extension	OBJ
Full Name	Wavefront
Type	3D Model
Mime Type	text/plain
Format	Text
Opens With	MeshLab, CAD Assistant, DAZ Studio

The OBJ file format is a 3D graphics file format used to define complex 3D models, including geometry, materials, and textures. OBJ files are text files, making them human-readable and easy to modify by hand. The downside to this ease of readability is that the files can become rather large when dealing with large or complex 3D models.

As mentioned, the OBJ format stores not only 3D model geometry but also materials and textures. These materials are usually defined in a separate file with the MTL file extension and specify geometry rendering details such as diffuse and specular colour, transparency, and much more.

The OBJ material file can also reference external texture files. These are usually JPEG or PNG files; however, these can be older formats, such as TGA. Where materials are used, the OBJ file will also contain material names preceding the geometry faces they should be applied to. If textures are referenced, the geometry will also contain texture coordinates (UV) for each vertex.

OBJ Converter Capabilities

When converting your STL to OBJ, our tool will attempt to accurately convert any colour or material information.

Information for converting from STL to OBJ

Your STL file will be converted to a OBJ file using our unified 3D model and mesh conversion tool. Our STL 3D tool performs accurate conversions of 3D elements such as vertices, faces, normals, and relevant material information. As both STL and OBJ support colour material information, our tool will also attempt to convert the colour information.