Rescale STL/OBJ/GLB meshes between inches, cm, and mm in one click. Browser-based — no upload, no calibration headaches.
Upload your model and choose the source and target units
We multiply every vertex by the conversion factor (1 inch = 25.4 mm)
Download the rescaled model — the geometry is identical, just resized
0 bytes uploaded. 3D Unit Converter runs entirely in your browser using three.js and WebGL. Your meshes never leave your device.
No. The original is never modified. We download a new file with the converted dimensions.
STL has no unit metadata — printers assume mm by default. If your model imports at 25.4× the wrong size, it was authored in inches.
Yes. STL stays STL (binary), OBJ stays OBJ, GLB stays GLB with materials and animations intact. Only the vertex coordinates are scaled.
Auto-scale STL/OBJ/GLB models to fit any printer bed (X/Y/Z mm). Maintains proportions. Browser-based, no upload.
Open toolCompute the X/Y/Z bounding box of any STL, OBJ, or GLB mesh. Get exact print dimensions in mm — useful for fitting models to your printer bed.
Open toolConvert STL files to GLB (binary glTF) directly in your browser. Smaller, faster, and AR-ready. Zero upload — your meshes never leave your device.
Open tool