Layer height is the vertical thickness of each individual layer a 3D printer deposits or cures, measured in microns or millimeters, and the primary setting governing the tradeoff between print resolution and print speed.
Layer height, also called layer thickness or vertical resolution, defines how thick each cross-sectional slice of a print is along the Z-axis. It is one of the most consequential choices in 📝3D printing, set in the slicer before a job begins, and commonly ranges from roughly 10 to 400 microns depending on the machine — filament printers often work near 100–300 microns while resin printers reach finer values. On extrusion printers the achievable range is bounded by the nozzle diameter; on resin printers it is governed by the light source and Z-axis precision.
The setting is the main lever over surface quality. A smaller layer height produces finer detail, smoother curves, and less visible layer lines, because each step in the Z direction is smaller. It is only one component of overall resolution, which also depends on horizontal (X and Y) accuracy; layer height specifically describes the vertical dimension.
Layer height trades quality against time. Halving the layer height roughly doubles the number of layers and therefore the print duration — moving from 100 to 25 microns can lengthen a print roughly fourfold — while also raising the chance of a failed job. Slicing settings therefore balance layer height against the required detail, the part geometry, and an acceptable print time.