Free online PNG to STL converter

Your STL comes out as a watertight relief slab, not a paper-thin surface your slicer will reject. The top follows your image's brightness, the bottom is a flat base, and all four sides are closed with wall faces — so the slicer sees a printable solid on the first try. You control the physical result: model width sets the scale in millimeters, relief height sets how far your brightest details stand above the base, and base thickness puts enough material underneath to keep the part sturdy. Mesh resolution sets how many columns of your image get sampled, capped so it stays fast in your browser. Higher resolution keeps sharper edges but means more triangles and a larger STL file; lower resolution slices faster and often prints better for simple signs or coarse FDM work.

Your best results come from images with clear silhouettes, strong contrast, and little noise. Logos, black-and-white icons, embossed labels, simple maps, game tokens, maker plates, and stencil-like artwork all convert cleanly — and a grayscale heightmap, like terrain data, is the ideal input. A photo is harder: texture, shadows, compression blocks, skin tones, and background clutter all become height changes, so a portrait or product photo may technically convert but look like noisy terrain. If your STL surface looks grainy, raise smoothing, lower the resolution, or clean up the source image first. Converting a JPG to STL instead? Use the cleanest original you have, because JPEG compression artifacts can turn into tiny bumps on your print.

You want a relief if your print should read by daylight, from its surface: an embossed logo, sign, stamp plate, terrain tile, plaque, or decorative texture. That is what this PNG to STL tool makes — your image's brightness becomes raised or recessed height you can see and touch, no backlight needed. You want a lithophane if your print should glow from behind: lithophanes are designed for light passing through thin translucent material, so darker image regions are usually printed thicker, and the final result depends on backlighting, wall thickness, and filament or resin translucency. For a backlit photo, use a dedicated lithophane workflow like the Color Lithophane Maker linked below; for a raised shape from an icon or drawing, you are already in the right place.

Your STL carries only triangles — no source image, color, transparency, or units — so give it a quick look in a slicer before printing. The dimensions are exported in millimeters by convention, but your slicer may still allow scaling, so confirm the size. Then check three things: the base is thick enough for your nozzle or resin settings, the raised details are not finer than your printer can hold, and the model lies flat on the build plate. That is all a flat relief needs. If what you actually want is a complete printable object with real 3D structure instead of a raised image, hand your picture to PrintReady3D's AI image-to-3D model generator instead.