Magic Layer Heights
Layer heights that are whole multiples of a full Z step avoid the tiny rounding errors that show up as banding. Pick your Z drive and get the list.
How it's calculated
full step = lead per revolution / (steps per revolution × gear ratio) magic heights = n × full step (n = 1, 2, 3 …)
- A 1.8° motor turns 200 full steps per revolution. On a T8×8 lead screw (8 mm per turn) that is 0.04 mm per full step, so 0.12, 0.16, 0.20 and 0.24 mm are “magic”; 0.15 mm is not.
- Microstepping positions between full steps are less accurate because motor torque there is lower, which is why whole steps are preferred.
- Prusa MK3/MK4 and Voron 2.4 also land on 0.04 mm full steps (8 mm per motor revolution; 400–800 steps/mm depending on microstepping), which is why 0.05 and 0.15 mm are not quite magic on them either. A 0.9° motor or a 2 mm-lead screw halves or quarters the step, so almost every common height becomes magic.
Questions people ask
What are magic numbers in 3D printing?
Layer heights that are exact multiples of your Z motor's full-step distance, so every layer change lands on a full step rather than a microstep.
Do magic layer heights matter on modern printers?
Less than they used to — good drivers and belted Z reduce the effect — but they cost nothing, so there is no reason to pick 0.15 mm on an Ender 3 when 0.16 mm is free.