# Calibrate extrusion multiplier

After the extruder has been calibrated, we now know that the extruder feeds the right amount of filament into the hotend. Now we can calibrate based on how the filament flows out of the nozzle. We do this by printing a cube ( Download ) with the following parameters : two circumferential envelopes, no infill, no top layer, a lower solid layer, extrusion width nozzle diameter * 1.2 (with 0.4 mm nozzle this would be 0.48 mm) and extrusion's multiplier = 1

### After printing

After the printing has been completed, let the workpiece cool and then measure all four sides of the cube from above approx. 1–2 mm as can be seen in the photo. Now calculate the average wall thickness by adding all four measured values and dividing them by four, for example:
1.02 + 1.03 + 1.02 +1.02 = 4.09 / 4 = 1.02

### Calculation of the extrusion's multiplier

Now we calculate with this formula: (should wall thickness / measured wall thickness) * Extrusion's multiplier = new extrusion's multiplier, the new extrusion's multiplier. This then results in (0.96 / 1.02) * 1 = 0.94. In our example 0.94 would be our new extrusion's multiplier. Now enter this new extrusion's multiplier in your slicer and reprint the cube after which it was printed, check the wall thickness, this should now be 0.96 mm. Please make sure that the outer walls stick together, if you don't, increase the extrusion's multiplier by 1% (0.01) until the outer walls are firmly connected.

### Extrusion's multiplier calculator

Please enter your measurements in the form below:

Side 1: mm
Side 2: mm
Side 3: mm
Side 4: mm

Extrusion multiplier:

Extrusion width: mm

New extrusion multiplier: 0