G425 - Backlash Calibration

calibration Use a conductive object to calibrate XYZ backlash CALIBRATION_GCODE


This command performs an automatic calibration of backlash, positional errors, and nozzle offset by touching the nozzle to the sides of a bed-mounted, electrically-conductive object (e.g., a cube, washer or bolt).

This command measures backlash but doesn’t enable backlash correction. Use M425 to enable backlash correction.


Requires CALIBRATION_GCODE and the following parameters:

  • CALIBRATION_MEASUREMENT_RESOLUTION determines the increments taken in mm when performing measurements.
  • CALIBRATION_FEEDRATE_SLOW, CALIBRATION_FEEDRATE_FAST and CALIBRATION_FEEDRATE_TRAVEL determine the speed of motion during the calibration.
  • CALIBRATION_NOZZLE_TIP_HEIGHT and CALIBRATION_NOZZLE_OUTER_DIAMETER refer to the conical part of the nozzle tip.
  • CALIBRATION_REPORTING enables G425 V for reporting of measurements.
  • CALIBRATION_OBJECT_CENTER and CALIBRATION_OBJECT_DIMENSIONS define the true location and dimensions of a cube/bolt/washer mounted on the bed.
  • CALIBRATION_MEASURE_RIGHT, CALIBRATION_MEASURE_FRONT, CALIBRATION_MEASURE_LEFT and CALIBRATION_MEASURE_BACK define the usable touch points. Comment out any sides which are unreachable by the probe. For best results, all four sides should be reachable.
  • CALIBRATION_PIN, CALIBRATION_PIN_INVERTING, CALIBRATION_PIN_PULLDOWN and CALIBRATION_PIN_PULLUP configure the pin used for calibration. For example, if the nozzle is grounded, the calibation cube would be connected to a digital input pin with a pull-up enabled.


G425 [B] [T<index>] [U<linear>] [V]



Perform calibration of backlash only.


Perform calibration of one toolhead only.


Uncertainty: how far to start probe away from the cube (mm)


Probe cube and print position, error, backlash and hotend offset. (Requires CALIBRATION_REPORTING)