Free Online Image to STL Converter
Convert 3D model files to STL instantly in your browser. 100% private — files never leave your device. No sign-up, no upload, no limits.
How to Convert to STL
Upload your 3D model
Click the upload area or drag and drop your 3D file (OBJ, GLB, PLY, FBX and more). Files are parsed locally in your browser — nothing is uploaded to a server.
Preview in 3D
Inspect your model in the interactive 3D viewport before converting. Rotate, zoom, and verify the mesh looks right.
Convert & download STL
Click Convert to generate the STL file, then download it instantly. Ready for 3D printing slicers like Cura, PrusaSlicer, or Bambu Studio.
Why Choose Our Converter
100% In-Browser
Conversion runs locally via three.js + WebAssembly. Your files never leave your device — fully private and secure.
No Sign-Up, No Limits
Free with no account required. Convert as many files as you want, up to 50MB each, with no daily caps.
Instant 3D Preview
See your model rendered in real-time before downloading. Catch geometry issues before slicing.
3D-Print Ready
STL output is optimized for FDM, SLA, and SLS workflows. Compatible with every major slicer and printer.
3D Model vs STL Format Comparison
| Feature | OBJ | STL | 3MF |
|---|---|---|---|
| Full name | Wavefront OBJ | Stereolithography | 3D Manufacturing Format |
| Geometry | Vertices, faces, normals | Triangles only | Triangles (manifold-safe) |
| Color / texture | Yes (separate MTL) | No | Yes (embedded) |
| Multi-material | Yes (multi-file) | No | Yes (single file) |
| 3D printing | Partial support | Industry standard | Modern standard |
| File size | Medium | Large (redundant) | Small (compressed) |
| Best for | Modeling, rendering | Universal printing | Multi-color printing |
What Is an STL File?
STL (StereoLithography) is the de facto standard file format for 3D printing. Created in 1987 for stereolithography machines, STL describes only the surface geometry of a 3D object as a mesh of triangles — storing no color, texture, or material data. Because every major slicer (Cura, PrusaSlicer, Bambu Studio) and 3D printer reads STL natively, it remains the most universally compatible format for FDM, SLA, and SLS printing workflows.
An STL file represents a model using a list of triangular facets, each defined by three vertices and a normal vector. A typical print-ready STL contains anywhere from a few thousand to several million triangles depending on model complexity and desired print resolution. Lower triangle counts produce smaller files but rougher curves; higher counts yield smoother surfaces at the cost of larger file sizes.
Where STL fits in the 3D printing pipeline: (1) Design — model in CAD software (Blender, Tinkercad, Fusion 360) and export as .stl; (2) Slicing — import the STL into a slicer (Cura, PrusaSlicer, Bambu Studio) which cuts the mesh into flat 2D layers; (3) Printing — the slicer converts layers into G-code, the machine language that drives the printer's motion and extrusion.
Pros and cons of STL
Pros: STL is the "JPEG of 3D models." Because it is simple and has existed since the 1980s, it is universally compatible with virtually every 3D printer and slicer. The format is well-understood, easy to generate, and ubiquitous in the printing community.
Cons: STL stores only X, Y, Z triangle coordinates — no color, material, scale units, or assembly data. Shared vertices are saved redundantly per triangle, making high-detail files large. A low triangle count produces faceted, low-resolution curves. These limitations are why the newer 3MF format was created.
Last updated: July 2026. Format details reference the STL file format specification.
How to Turn a 2D Image Into an STL
There are three common ways to convert a flat image (JPG, PNG, WEBP) into a 3D-printable STL file, each suited to a different kind of input:
1. Heightmap conversion (logos, lithophanes)
A heightmap converter maps pixel brightness to 3D depth: dark pixels become recessed, light pixels become raised. This is the standard method for lithophanes (photos that reveal detail when backlit) and high-contrast logos. Use a high-contrast image for the cleanest result.
2. SVG trace + extrude (line art, shapes)
Convert the image to an SVG vector path using a tracing tool (PicSVG, Adobe Illustrator), then import the SVG into Tinkercad or Blender and extrude it into a solid mesh. This gives precise control over thickness and is ideal for icons, text, and flat signage.
3. AI image-to-3D generation (photos, sculptures)
Modern AI generators infer full 3D geometry from a single photo, producing a textured mesh you can export as STL. This is the fastest route for figurines, busts, and organic shapes that are hard to model by hand. Trify3D's Image to 3D tool covers this workflow end-to-end.
For models that already exist in a 3D format (OBJ, GLB, PLY, FBX), skip all of the above and use the converter on this page to export STL directly.
Frequently Asked Questions
Is the image to STL converter really free?
Yes. The tool is 100% free with no sign-up, no watermarks, and no file limits. Conversion happens entirely in your browser.
Are my files uploaded to a server?
No. All parsing and conversion runs locally in your browser using three.js and WebAssembly. Your files never leave your device.
What input formats are supported?
OBJ, GLB, glTF, PLY, FBX, 3MF, Collada (DAE), STL and more. The converter auto-detects the format from your file and outputs STL.
What is the maximum file size?
Up to 50MB per file. Larger files may take longer to process depending on your device's CPU and memory.
Will textures and colors be preserved?
STL is a geometry-only format — it stores mesh shape but not colors or textures. Only the 3D geometry from your model is converted to STL.
Do I need to install any software?
No. The converter runs in any modern browser (Chrome, Firefox, Safari, Edge) with WebGL support. No downloads or plugins required.
Can any 3D printer print STL files?
Yes. STL is the universal standard for 3D printing and virtually every printer and slicer — including Cura, PrusaSlicer, Bambu Studio, and Chitubox — reads STL natively. Whether you use FDM, SLA, or SLS, STL files are compatible out of the box.
What are the disadvantages of STL files?
STL stores only surface geometry, so it cannot hold color, texture, material, or multi-part assembly data. Files can be large because shared vertices are stored redundantly per triangle, and a low triangle count produces blocky, faceted curves. This is why the newer 3MF format was created.
STL vs 3MF: which is better?
3MF is the modern successor to STL. It is a compressed XML format that stores full color, materials, multiple objects, and print settings (infill, supports) in a single file, with smaller sizes and manifold-safe meshes. STL is still the safest choice for maximum compatibility, but 3MF is increasingly preferred for multi-color and multi-material printing.
STL vs STEP: which should I use?
STEP (ISO 10303) stores mathematically exact solid B-rep geometry and is the standard for engineering and CAD interchange. STL approximates a model with triangles and is the standard for 3D printing. Use STEP for mechanical design, tolerancing, and CNC; convert to STL only when you are ready to slice and print.
Are CAD and STL the same?
No. CAD files (STEP, IGES, native SolidWorks/Inventor) describe precise, editable solid geometry with parametric history. STL is a dumb tessellated mesh — a frozen approximation of the surface with no design intelligence. Exporting from CAD to STL is a one-way conversion.
How do I create an STL file?
Export one from any 3D modeling tool — Blender, Tinkercad, Fusion 360, FreeCAD, Onshape, and SolidWorks all support STL export. For 2D images, convert the image to an SVG first, then import the SVG into Tinkercad or Blender and extrude it into a mesh before exporting STL. This tool lets you skip the modeling step by converting an existing 3D file directly to STL.
How do I turn a 2D image into an STL?
Three common methods: (1) Use a heightmap converter that maps dark/light pixels to 3D depth — ideal for lithophanes and logos. (2) Trace the image into an SVG with a tool like PicSVG, import it into Tinkercad, and extrude. (3) Use an AI image-to-3D generator to produce a full mesh from a photo, then export STL.
How long does conversion take?
For files under 50MB, conversion typically completes in a few seconds because it runs locally on your device using your CPU and GPU. No upload or download step means no network bottleneck.
Need More Conversion Options?
Open the full Convert Studio to convert between every supported 3D format — GLB, glTF, OBJ, PLY, FBX, 3MF, USDZ and more.
Open Convert Studio