Free · Browser-Based · Private

Free Online CAD & 3D File Converters

Convert engineering and 3D model files directly in your browser. No upload, no signup, no size limits — your files never leave your device. Built by engineers, for engineers.

STL ↔ OBJ

Live

STL ↔ OBJ Converter

Bidirectional conversion with built-in 3D preview. Handles both binary and ASCII STL up to 250 MB.

Open converter

STL → GLB / glTF

Live

STL → GLB / glTF

Web-ready 3D models for AR viewers, embeddable previews, and game engines. Compact binary glTF output.

Open converter

OBJ ↔ GLB / glTF

Live

OBJ ↔ GLB / glTF

Bidirectional conversion for web 3D, AR, Sketchfab uploads, and game engines. Accepts GLB and glTF input too.

Open converter

STEP → STL / OBJ

Soon

STEP → STL / OBJ

Convert parametric CAD models (.step, .stp) to mesh formats for 3D printing and visualization.

In development

DXF → PDF

Soon

DXF → PDF

Export AutoCAD-compatible drawings to shareable PDF with scale and layout preserved.

In development

IFC → OBJ / GLB

Soon

IFC → OBJ / GLB

Extract BIM geometry from IFC files for use in mesh-based pipelines, web viewers, and rendering tools.

In development

No converters match your filter. Try a different format name.

Privacy

100% Private

Files are processed in your browser. They never touch a server — verify it yourself in DevTools.

Performance

No Size Limits

Unlike most online converters, no daily quotas or watermarks. Limited only by your device’s RAM.

Practical

Engineer-Built

By civil and structural engineers. We use these tools ourselves for FreeCAD, Blender, and slicers.

Why convert in the browser?

Most online converters upload your file to a server, queue it, process it remotely, and let you download the result. That works — but it means your design data sits on someone else’s machine, queued behind other people’s files, and capped by their plan limits. For sensitive engineering work (NDA-bound projects, proprietary geometry, internal designs), that’s often a non-starter.

Buildref converters run entirely on your machine using WebAssembly and JavaScript. The conversion happens locally, with no network traffic during the actual processing. You can verify this yourself by opening your browser’s DevTools and watching the Network tab during a conversion — it stays empty.

FAQ

Are these converters really free? What’s the catch?

No catch. No signup, no watermark, no daily limit, no email harvesting. These tools cost us essentially nothing to run because they execute in your browser, not on our servers. We built this site partly as a calling card for our engineering work and partly because we needed these tools ourselves.

Why convert in the browser instead of using desktop software?

Two reasons. First, speed — no installation, no licensing dance, just drop a file and download the result. Second, privacy — for sensitive engineering data, keeping the file local matters. Desktop tools like FreeCAD or Blender also do these conversions, but they’re overkill for a quick format swap.

Which format should I use for 3D printing?

STL is the universal standard — every slicer (Cura, PrusaSlicer, Bambu Studio) accepts it. 3MF is the newer alternative that preserves color and material info, but STL has wider tool support. If you have a model in OBJ or STEP, convert it to STL before sending to your slicer.

Can I use the converted files for commercial work?

Yes. There are no licensing restrictions on the files you produce here. The tools are provided as-is for personal and commercial use. The original copyright of the model you’re converting stays with whoever owns it — we don’t claim any rights to files you process.

Do you store any data about my conversions?

We don’t store your files because they never reach us. Like any website, we use standard analytics to count page visits — this is anonymized and contains no file information. See our Privacy Policy for details.

I need a converter that’s not listed here. Can you build it?

Possibly. We’re actively expanding the list based on what users need. If you’ve hit a wall converting a specific format pair, get in touch — we read every request and prioritize the ones that come up repeatedly.