3D Printing Feed (Small-Scale) Calculator
Calculate filament feed rate and volumetric flow for a small-scale FDM 3D print from your nozzle settings, layer height and print speed.
Overview
This small-scale 3D printing feed calculator estimates the filament push speed and volumetric flow needed for an FDM print. Enter your filament diameter, extrusion line width, layer height, print speed and flow setting to check whether the requested flow is reasonable for your hot end.
How it works
The calculator estimates the cross-sectional area of a deposited extrusion line by multiplying line width by layer height. It then multiplies that area by print speed and your flow multiplier to estimate volumetric flow in cubic millimetres per second. Finally, it divides that volume by the cross-sectional area of the input filament to estimate how fast the extruder must feed filament. The capacity percentage compares the required flow with the maximum flow value you enter.
How to use this calculator
- 1Measure or enter the filament diameter used by your printer.
- 2Enter the line width and layer height from your slicer profile.
- 3Add the intended print speed for extrusion moves.
- 4Set the flow multiplier used in your slicer.
- 5Enter an estimated maximum volumetric flow for your hot end.
- 6Review the required filament feed rate and flow capacity used.
Example Calculation
Filament diameter
1.75
Line width
0.45
Layer height
0.2
Print speed
50
Flow multiplier
100%
Printer maximum volumetric flow
10
Required filament feed rate
1.87 mm/s
These settings require about 2.25 mm³/s of volumetric flow and approximately 0.94 mm/s of 1.75 mm filament feed, using around 22.5% of a 10 mm³/s flow limit.
Frequently asked questions
What is filament feed rate in 3D printing?
Filament feed rate is the linear speed at which the extruder pushes filament into the hot end. It is usually expressed in millimetres per second or millimetres per minute.
What is volumetric flow in an FDM printer?
Volumetric flow is the volume of melted plastic the hot end must deliver each second, usually measured in mm³/s. It rises when line width, layer height, flow multiplier or print speed increases.
Why does filament diameter affect feed rate?
Thicker filament has a larger cross-sectional area, so less linear filament movement is needed to supply the same volume of plastic. A 1.75 mm setup therefore needs a higher feed speed than a 2.85 mm setup at the same volumetric flow.
How do I find my printer's maximum volumetric flow?
A practical limit can be found through a controlled flow or speed test for the specific filament, nozzle, temperature and hot end. Manufacturer guidance can be a useful starting point, but real limits vary by setup.
What happens if the required flow is too high?
If the hot end cannot melt and deliver plastic quickly enough, the print may show under-extrusion, gaps, inconsistent lines, poor layer bonding or extruder skipping.
Does this calculator account for acceleration and travel moves?
No. It estimates steady extrusion demand at the entered print speed. Actual motion includes acceleration, deceleration, corners, retractions and travel moves, so instantaneous behavior can differ.
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Assumptions and warnings
Assumptions
- The deposited extrusion bead is approximated using line width multiplied by layer height.
- The selected print speed is treated as the speed during active extrusion, not travel movement.
- The flow multiplier is applied uniformly throughout the print.
- Maximum volumetric flow depends on the hot end, nozzle, filament, temperature and cooling conditions.
- Results are planning estimates; actual extrusion demand varies with path geometry and slicer behavior.
Warnings
- Exceeding the hot end's practical volumetric-flow limit can cause under-extrusion, weak layers, poor surface quality or missed steps.
- Check actual extrusion and print quality with a small test before using high-speed settings on an important print.