Enter your current extruder calibration in steps/mm and the commanded and measured filament lengths in mm. The calculator returns the corrected steps/mm value and a dimensionless correction factor.
Use the calibration value active during the measurement. Enter actual filament travel, not the distance remaining to a reference mark or the length of material leaving the nozzle.
Accepted calibration values are 0.001–100,000 steps/mm in increments of 0.001. Both lengths accept 0.01–10,000 mm in increments of 0.01. These are calculator input limits, not recommended printer operating ranges. Zero and negative values are invalid.
Values are entered as numerical magnitudes in the units printed in each label. The calculator stores these magnitudes as scalars; enter both lengths in mm and calibration in steps/mm. Displayed decimal places do not establish measurement accuracy.
The formula generalizes the 100 mm E-steps calculation in Ellis’ Extruder Calibration guide to a variable commanded length. Measured travel below the commanded length increases the calculated steps/mm; measured travel above it decreases the value. Equal lengths leave calibration unchanged.
The calculation assumes repeatable filament motion. Slipping or inconsistent measurements can make the result misleading. This is a steps-per-length calculation; rotation-distance settings require a different relationship.
| Current calibration (steps/mm) | Commanded length (mm) | Measured travel (mm) | Calculation | Corrected calibration (steps/mm) |
|---|---|---|---|---|
| 100 | 100 | 95 | 100 × 100 ÷ 95 | 105.2632 |
| 100 | 100 | 105 | 100 × 100 ÷ 105 | 95.2381 |
| 415 | 100 | 100 | 415 × 100 ÷ 100 | 415.0000 |
| 400 | 50 | 48 | 400 × 50 ÷ 48 | 416.6667 |
The outputs are numeric estimates. This tool does not generate firmware commands or control a printer. Repeat the measurement to check consistency before relying on the correction. An unavailable calculation is not a zero result: check for missing values, invalid bounds or a zero divisor.