STL Editor is a free tool. Upload an STL file to this STL editor, set the size in millimetres, rotate and mirror it, then preview and download the edited file for slicing.
Runs in your browser · your file is not uploaded · no sign-in needed
Configure your options
Your 3D Model Will Appear Here
Fill in the options on the left, then press the button. The work is done in your browser.
Relevant internal links based on this tool
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Drag & drop your file here or click to browse
An STL editor lets you resize, rotate, and mirror an STL file before you print it, without installing slicing software. Upload your model, set the longest side in millimetres or a percentage scale, choose rotation angles, and place the part flat on the bed. It suits hobbyists preparing a single print and anyone who needs a quick fix before slicing.
Select Upload an STL File and add the model you want to change. The file loads and previews in your browser, and it is never sent to a server, so it stays on your device the whole time.
Enter a Longest Side in millimetres or a Scale percentage, then pick Rotate Around X, Y, or Z in degrees and a Mirror direction if you need one. Turn on Place on the Print Bed to align the base flat.
Press Apply Changes to update the preview with your new size, rotation, and mirror settings. Check the model looks right, then download the edited STL file ready for your slicer.
A model sized for a large printer often needs shrinking to fit a smaller bed. Set the Longest Side in millimetres to the largest dimension your printer allows, and the rest of the model scales with it so proportions stay correct.
Files exported from some design tools land on their side or upside down. Rotate Around X, Y, or Z in 90 degree steps until the part sits the way you expect, then use Place on the Print Bed to drop it flat before slicing.
Left and right versions of the same part, such as a pair of brackets, do not need a second design. Mirror the model on the X, Y, or Z axis to get the opposite version, then export it separately from the original.
It lets you scale, rotate, mirror, and reposition an existing STL file, then export the result. It does not sculpt, cut, or add new geometry to the model, so it suits adjusting a file you already have rather than creating one from scratch.
No. It runs fully in your browser, so no account is required and no credits are used. Your file is never uploaded to a server, which also means it stays private to your device while you work on it.
There is no fixed number, but performance depends on your device's memory since the file never leaves your browser. Very large or high-detail models may load slowly or lag on older computers, so try a smaller test file first if you run into trouble.
STL stores the surface shape of a 3D model as a mesh of triangles, without colour or texture. It is the most common format for 3D printing because slicers read it to work out how to build the object layer by layer.
Check your printer's build volume, usually listed in millimetres for X, Y, and Z, and compare it with the model's current longest dimension. Scale the part down until its longest side fits inside that volume with some clearance for the print bed edges.
Mirroring flips a shape into its reverse form, which is useful for parts that come in matching pairs, like a left and right hinge, or for correcting a model that was designed back to front.
Fix mesh errors like holes or bad normals before you resize or reprint the model.
Convert your edited STL into OBJ, 3MF, or GLB once you are happy with the size and rotation.
Open and inspect an STL file in 3D without changing it, useful for a quick check first.
Turn a 3MF file into STL first if your model was exported in that format.
Your file stays on your device. It is not uploaded.