Rotation Distance Calculator

The Rotation Distance Calculator corrects your Klipper extruder calibration from a single measurement. Enter your current rotation_distance, how much filament you asked the printer to extrude, and how much it actually extruded — the calculator returns the corrected value.

Free, runs in your browser, no registration.

What rotation distance actually is

In Klipper, rotation_distance replaced the e-steps model used by Marlin. It is the distance the filament advances for one full rotation of the extruder motor shaft, measured in millimetres.

If the value is wrong, every print is wrong in the same direction:

• Rotation distance too high — the extruder under-extrudes. You get gaps between perimeters, weak layer adhesion, and visible voids in top surfaces.
• Rotation distance too low — the extruder over-extrudes. You get blobbing, rough top layers, elephant foot, and dimensional creep.

No amount of flow-rate or pressure-advance tuning compensates for a wrong rotation distance, which is why this is the first calibration to do on any new machine or extruder.

The formula

new_rotation_distance = old_rotation_distance × (actual_extrusion / requested_extrusion)

Worked example: your current value is 33.500, you request 100 mm, and you measure 98.5 mm of filament consumed.

33.500 × (98.5 / 100) = 32.9975

Your corrected rotation_distance is 32.998.

Note the direction: because the printer extruded less than requested, the rotation distance goes down.

Measurement procedure

Accuracy of the result depends entirely on accuracy of the measurement. The calculation is trivial; the measuring is where people go wrong.

1. Heat the hotend to your normal printing temperature for the loaded filament. Cold extrusion is blocked and warm-but-not-hot extrusion skips.
2. Mark the filament exactly 120 mm above a fixed reference point on the extruder body. Use calipers, not a ruler.
3. Extrude 100 mm at a slow rate:

   G91
   G1 E100 F60

   F60 is 1 mm/s. Extruding faster introduces skipping and pressure effects that corrupt the measurement.
4. Measure the remaining distance from your mark to the same reference point.
5. Actual extrusion = 120 − remaining. If 21.5 mm remains, you extruded 98.5 mm.
6. Enter all three numbers into the calculator.
7. Update printer.cfg under your [extruder] section, then RESTART.
8. Repeat once to verify. A correctly calibrated extruder lands within ±0.5 mm.

Common mistakes

• Measuring with the hotend cold. The filament path changes when hot; calibrate under printing conditions.
• Extruding too fast. Anything above about 5 mm/s risks motor skipping, which reads as under-extrusion that isn’t real.
• Using a ruler. A 0.5 mm reading error on a 100 mm test is a 0.5% error in every print you make afterward.
• Calibrating with a partially clogged nozzle. Back-pressure suppresses extrusion and you will “correct” a fault that isn’t in the extruder.
• Assuming the value transfers between filaments. Rotation distance is a property of the extruder, not the filament — but soft or oversized filament can read differently. Recalibrate if you switch to something very different (TPU in particular).

Related tools

• Lead Screw Rotation Distance Calculator — the same principle for Z axis lead screws
• Pressure Advance Calculator — tune after rotation distance is correct
• Extrusion Rate Smoothing Calculator — for high-acceleration machines
• All Calculators — the full Minimal 3DP calculator suite

Calibration order

Rotation distance comes first. Everything downstream assumes the extruder moves the filament distance it claims to:

1. Rotation distance — the extruder tells the truth
2. Flow rate / extrusion multiplier — the right volume comes out
3. Pressure advance — the volume arrives at the right time
4. Extrusion rate smoothing — pressure advance stays stable under acceleration

Working out of order means retuning everything each time you fix a lower layer.

Verified configurations

The rotation distance values I run on my own machines — Voron 2.4, Creality K2 Plus, Ender 3 series, and Sovol SV08 — are published in my Klipper configs repository, free and open.

If you would rather not derive them yourself, the documented and version-tracked config packs include the calibration data, the test procedure, and notes on what to change when your hardware differs.