3D Printing Feed Calculator
Calculate volumetric flow and filament feed rate from your print speed, extrusion dimensions, filament diameter, and flow multiplier.
Overview
This 3D Printing Feed Calculator estimates the material flow required by a print move. Enter your layer height, line width, print speed, filament diameter, and flow multiplier to see the resulting volumetric flow and the filament feed rate your extruder must deliver.
How it works
The calculator first estimates the cross-sectional area of a printed line by multiplying layer height by line width. It multiplies that area by print speed and the flow multiplier to find the volumetric flow in cubic millimetres per second. It then divides that flow by the circular cross-sectional area of the filament to estimate how many millimetres of filament the extruder must feed each second.
How to use this calculator
- 1Enter the layer height and line width from your slicer profile.
- 2Add the print speed for the extrusion move you want to assess.
- 3Enter the actual or nominal diameter of your filament.
- 4Set the flow multiplier used by your slicer.
- 5Compare the volumetric flow result with your hotend's tested material limit.
Example Calculation
Layer height
0.2
Line width
0.42
Print speed
60
Filament diameter
1.75
Flow multiplier
100%
Volumetric Flow Rate
5.04 mm³/s
With a 0.20 mm layer height, 0.42 mm line width, and 60 mm/s print speed, the estimated flow is 5.04 mm³/s. A 1.75 mm filament needs to feed at about 2.10 mm/s, or 125.7 mm/min.
Frequently asked questions
What is volumetric flow in 3D printing?
Volumetric flow is the volume of filament material your printer must melt and deposit each second, usually expressed in mm³/s.
Why does filament diameter affect feed rate?
Thicker filament contains more material per millimetre of length. It therefore needs less linear movement than thinner filament to supply the same volume.
What volumetric flow rate can my hotend handle?
It varies with the hotend, nozzle size, filament type, nozzle temperature, and heater performance. Use tested limits for your specific setup and material.
Does a larger nozzle always require higher volumetric flow?
Not always, but a larger nozzle often uses wider and taller extrusion lines. At the same speed, those larger lines generally increase volumetric-flow demand.
Why might the calculated result differ from my slicer?
Slicers may model extrusion line shapes, overlap, acceleration, pressure control, and extrusion compensation differently. This calculator uses a simple line-area approximation.
Should I use the nominal or measured filament diameter?
Measured diameter can improve estimates when filament varies from its nominal size. Take several measurements along the spool and use a representative average.
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Assumptions and warnings
Assumptions
- The deposited extrusion line is approximated as a rectangle using layer height and line width.
- The flow multiplier is applied evenly to all extrusion moves.
- Filament is assumed to be round and consistently sized along its length.
- The result describes steady extrusion and does not account for acceleration, pressure advance, retraction, or nozzle pressure losses.
Warnings
- This calculator provides planning estimates only; actual extrusion performance depends on the printer, hotend, nozzle, material, and temperature.
- Do not exceed the practical volumetric-flow limit for your filament and hotend, as this can lead to under-extrusion or print defects.