Free Online STL to 3MF Converter

You can use our STL to 3MF 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 3MF converter will process each 3D model and present you with a download link for each file once completed.

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 3MF 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 3MF Online?

Here are two simple steps to convert your STL to 3MF 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 3MF

Click the download link to receive your 3MF file.

Frequently Asked Questions

How can I convert my STL file to 3MF?

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 3MF conversion has completed, you can download your 3MF file right away.

How long does it take to convert my STL to 3MF?

We aim to process all STL to 3MF 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 3MF conversion?

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

File format information for STL and 3MF

Full NameStandard Triangle Language
Type3D Model
Mime Typeapplication/
Opens WithBlender, 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 modeling 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 flavors: 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 color materials into a suitable format for use in the converted file.

Full Name3D Manufacturing Format
Type3D Model
Mime Typeapplication/

The 3MF file format was created as a standard storage medium for 3D models for use within the area of 3D printing. A 3MF file will contain 3D model data stored within an XML-formatted document with additional assets such as image previews and material data. These files are wrapped up within a compressed ZIP file (using the 3MF extension).

The 3MF format was created in response to the constraints of the STL format, which is the most popular format for storing 3D printable models. Unlike the STL format, which can only store triangular information, the 3MF format can store mesh geometry along with material, units of measurement, and other relevant 3D printing information that is impossible to store within an STL file.

Storing the 3D data within a ZIP file container ensures the file size is kept to a minimum while making it easily extendable in the future. 3MF files are widely supported by 3D printing slicer software and are a common export option within 3D editing software.

3MF Converter Capabilities

When converting your STL to 3MF, our tool will attempt to accurately convert any color or material information.

Information for converting from STL to 3MF

Your STL file will be converted to a 3MF 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 3MF support color material information, our tool will also attempt to convert the color information.

Comparing STL and 3MF Files

While both STL and 3MF files are capable of storing complex 3D models and both have widespread support amongst the 3D printing community, we will delve a little deeper into both formats to try to work out the scenarios where one format would be preferred over the other.


Let's start with the basics. Both 3MF and STL files are capable of storing 3D mesh geometry; however, they both do this in different ways. With STL files, the geometry is represented by a simple list of triangles, each with three vertices that define the points of the triangle in 3D space. Along with these vertices is a single-face normal vector, which expresses the direction the face is pointing. It is quite striking when comparing this to how the 3MF format stores its geometry. The 3MF format uses indexed lists of vertices to define the surface geometry of the 3D object, which is a more efficient way of storing 3D geometry than the flat triangle list used by STL files. On top of this, the 3MF format also supports object colors and textures. It also contains other metadata specific to 3D printing, which makes the 3MF format more appropriate if you intend to 3D print your object.


While both files can be used to store and transmit 3D objects, they are both intricately linked to 3D printing. The STL format is the older of the two formats, has been around since the mid-1980s, and was never designed with 3D printing in mind. It has taken on the role of being the format of choice for distributing 3D printable models due to its simple file structure that is easy to implement within 3D printing slicer software and its widespread support within 3D applications. You will almost always find an "Export to STL" option within any 3D modeling application.

The 3MF file format, on the other hand, is a much more modern format that was designed from the start for 3D printing. As well as storing the 3D geometry in a more efficient format and being able to contain surface textures, it can also contain important metadata information used by 3D printers, for example, the units of scale such as millimeters, centimeters, meters, inches, etc.

Along with all these features is the added bonus that 3MF files are compressed with the same technology that is used by ZIP files, ensuring your 3MF files are small and efficient to transmit. STL files, on the other hand, are not compressed and can become quite large with more complex 3D objects.

A scanned person in STL format

A scanned person in STL format

A 3MF 3D printable battery container

A 3MF 3D printable battery container

A wind-up clock key 3D print file

A wind-up clock key 3D print file


For the broadest compatibility with 3D modeling and 3D printing slicer software, the STL format has the edge. It is also the most common format for distributing 3D printable models. If you download a 3D printable file from the web, the chances are it will be in the STL format. The 3FM format, however, is still relatively new, with support still being implemented in 3D modeling and 3D printing software, so it still has some way to go.

If the model you wish to 3D print needs to contain units of measurement data or is a multi-color print, the 3MF format would be the obvious choice to save your model to.

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