What is volumetric flow rate?

It is the volume of plastic extruded per second, measured in mm³/s. It determines how fast your hot end needs to melt filament. Most standard hot ends cap around 10-15 mm³/s.

What happens if I exceed my hot end flow rate?

Under-extrusion. The extruder cannot push filament fast enough through the melt zone, causing gaps, weak layers and potentially skipped steps on the extruder motor.

How do I find my hot end maximum flow rate?

Print a volumetric flow test. Gradually increase speed while monitoring extrusion quality. The point where under-extrusion begins is your maximum volumetric flow rate.

3DPrintCalcs

Flow Rate Calculator — Volumetric Extrusion

Calculate volumetric flow rate from print speed, layer height and line width.

Print Speed

Layer Height

Line Width

How We Calculate This

Formula

Flow rate = Print speed x Layer height x Line width (mm\u00B3/s)
Filament feed speed = Flow rate / Filament cross-section area

The filament feed speed tells you how fast the extruder gear must push the filament to achieve the desired flow rate.

Frequently Asked Questions

Related Calculators

Layer Height Calculator

Find optimal layer heights based on your nozzle size and desired quality.

Print Speed Calculator

Calculate maximum print speed based on volumetric flow rate and layer dimensions.

Infill Calculator

Estimate material usage and print time for different infill percentages and patterns.

Wall Thickness Calculator

Calculate wall thickness from number of perimeters and nozzle/line width.

Print Time Estimator

Estimate total print time from layer count, speed and travel moves.

Last updated: February 2026

All calculations are estimates. Always verify settings with test prints before committing to final prints.