What is an extrusion multiplier?

It is a scaling factor your slicer applies to every extrusion move. A value of 1.0 means the slicer trusts the printer to extrude exactly the length requested; any other value compensates for consistent over- or under-extrusion.

How do I measure the actual extruded length?

Mark the filament a fixed distance (commonly 100mm) above the extruder inlet, command that same length to extrude, then measure the new distance from the mark to the inlet. Actual length equals the starting mark distance minus the remaining distance.

Is this the same as flow rate percentage in Cura or PrusaSlicer?

Yes conceptually. A calculator result of 1.05 corresponds to a 105% flow rate; a result of 0.95 corresponds to 95%. Enter it in whichever field your slicer uses.

What if my result is far from 1.0?

A result outside roughly 0.9 to 1.1 usually points to a mechanical issue, such as a slipping extruder gear, wrong filament diameter setting, or a partially clogged nozzle, rather than something flow rate alone should fix.

Should I recalibrate for every filament?

Different materials and even different spools can extrude slightly differently. Recalibrating when you notice print quality issues, or after switching brands, keeps the multiplier accurate.

Does this replace E-steps calibration?

No. E-steps calibration corrects the extruder motor itself in firmware, while the extrusion multiplier is a per-print slicer setting. Most users fix E-steps once, then use the multiplier for finer or material-specific adjustments.

Extrusion Multiplier Calculator

Name: Extrusion Multiplier Calculator
Availability: InStock
Author: Nham Vu

Enter the requested extrusion length, the actual measured length, and your current multiplier to get the corrected multiplier for your slicer.

Calibration Inputs

Requested extrusion length (mm)

Actual measured length (mm)

Current multiplier / flow rate

Enter your measurements to get the corrected multiplier

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Summary

Enter the requested extrusion length, the actual measured length, and your current multiplier to get the corrected multiplier for your slicer.

How it works

Mark a filament segment 100mm (or any known length) above the extruder gear.
Command the printer to extrude that length through the slicer or printer firmware.
Measure the remaining distance from the gear to your mark and subtract from the starting length to get the actual extruded length.
Enter requested length, measured actual length, and your current multiplier below.
The tool multiplies your current value by requested/actual to give the corrected multiplier.
Enter the corrected multiplier into your slicer's flow rate or extrusion multiplier setting.

Use cases

Calibrate a new hotend or extruder after a hardware swap.
Fix visible over-extrusion (blobbing, oozing) or under-extrusion (gaps, weak layers).
Recalibrate after switching filament brands or materials with different diameters.
Dial in flow rate for a new nozzle size.
Verify extrusion accuracy as part of routine printer maintenance.
Cross-check a slicer flow percentage against a firmware E-steps value.

Frequently Asked Questions

Last updated: 2026-07-21 · Reviewed by Nham Vu