stl

.stl — Stereolithography File

3D Systems · 1987

Developer

3D Systems

What is a .stl file?

STL (Stereolithography) is the most widely used file format for 3D printing. It describes the surface geometry of a 3D object using triangular facets without any color, texture, or material information. STL files come in both ASCII and binary formats, with binary being preferred for its smaller file size. The format's simplicity makes it universally supported by 3D printers, slicers, and CAD software.

Programs That Open .stl Files

Platform	Program
Windows	3D Builder	Free	Official
	Blender	Free
	Cura	Free
macOS	Blender	Free
	MeshLab	Free

Common Problems with .stl Files

⚠️ Cannot open .stl file

Install one of the recommended programs listed above. For a free option, try the first free program in the list.

⚠️ .stl file is corrupted

Try re-downloading the file. If the file was transferred, ensure the transfer completed without errors.

Frequently Asked Questions

What program opens .stl files?▼

.stl files can be opened with several programs. 3D Builder is one of the most popular choices.

Is .stl a safe file format?▼

Generally yes, .stl files are safe to open with appropriate software.

Can I convert .stl to another format?▼

Yes, there are many online and offline tools available to convert .stl files. Check the conversion section above for specific methods.

Technical Details

Stereolithography File files use the application/sla MIME type and were first introduced in 1987 by 3D Systems. The file can be identified by its signature: 73 6F 6C 69 64 (solid, ASCII) or 80 bytes header (binary).

Did You Know?

Stereolithography File was first released in 1987 by 3D Systems

Security Information

.stl files are generally safe to open. However, always ensure your software is up to date to protect against potential vulnerabilities.