First layer height is one of the most critical FDM settings. A properly calibrated first layer creates the adhesion foundation for the entire print. This calculator computes the optimal first layer height and width based on your nozzle diameter and bed surface type.
Printer Settings
Recommended Settings
How to Set the Optimal First Layer Height
First layer settings determine whether your print sticks to the bed and whether the foundation is solid. The relationship between nozzle diameter and first layer height is straightforward: aim for 60-80% of nozzle diameter in height and 100-120% of nozzle diameter in width.
Height: The Squish Factor
First layer height determines how much the nozzle compresses the extruded filament against the bed. At 75% of nozzle diameter, the filament is squished flat enough to create excellent mechanical contact without being over-compressed. Under-squishing (too high Z offset) creates a rounded first line with poor adhesion; over-squishing grinds filament into the surface and can damage PEI coatings.
Width: Overlap Matters
First layer width is typically set at 100-120% of nozzle diameter. A wider first layer (110-120%) creates more overlap between adjacent lines, improving adhesion on rough surfaces like textured PEI. For smooth surfaces, 100-105% is sufficient. Many slicers allow setting first layer width as a percentage of nozzle diameter separately from subsequent layers.
Speed: Slow Down the First Layer
Regardless of overall print speed, set first layer speed to 20-30mm/s maximum. Slow first layers allow more accurate deposition and better material flow into the bed surface texture. High-speed first layers at 200+ mm/s skip over the bed without proper adhesion, leading to mid-print failures.
Frequently Asked Questions
Is this calculator free?
Yes, completely free with no signup required.
What is the ideal first layer height for a 0.4mm nozzle?
The recommended first layer height is 60-80% of nozzle diameter. For a 0.4mm nozzle, that is 0.24-0.32mm. Many slicers default to 0.2mm (50% of nozzle diameter), which works but a thicker 0.28-0.32mm first layer provides better adhesion by squishing more material into the bed surface.
Why is first layer height so important?
The first layer creates the foundation for the entire print. Too thin: insufficient material flow creates gaps and poor adhesion. Too thick: material can't squish properly onto the bed surface, causing detachment. The ideal first layer is 'squished' slightly — visibly flattened, not circular in cross-section. This maximizes contact area and mechanical interlocking with the bed surface.
What first layer height should I use for a textured PEI plate?
Textured PEI plates have microscopic surface texture that filament flows into for mechanical adhesion. Use a slightly thicker first layer (75-80% of nozzle diameter) to ensure material flows fully into the texture. For 0.4mm nozzle: 0.3-0.32mm first layer, with z-offset slightly lower (material closer to bed) than smooth surfaces.
How do I find my z-offset?
Z-offset is calibrated by the paper test: with bed at print temperature, slide paper under nozzle and lower Z until you feel slight drag. That position is your z-offset baseline. Adjust 0.01-0.05mm at a time: lower Z (more negative offset) for better squish, higher Z for less squish. Many printers have baby-stepping during first layer to fine-tune live.