3D Print Volumetric Flow Calculator

Enter your line width, layer height and print speed to see how much plastic your hotend must melt each second — and the fastest speed it can sustain.

Volumetric flow

5.4 mm³/s

Within your hotend's limit.

Filament feed

2.25 mm/s

Top speed at max flow

166.7 mm/s

Line width (mm)Layer height (mm)Print speed (mm/s)Filament diameter (mm)Hotend max flow (mm³/s)Optional

How it works

Type the extrusion line width and the layer height, in millimetres.
Enter the print speed in mm/s and the filament diameter (1.75 mm is the most common).
Optionally enter your hotend's maximum flow in mm³/s to get a safe top speed.
Read the flow in mm³/s and compare it with your hotend's limit.

Speeding up a print
Check whether raising the speed or the layer height still fits your hotend's melting capacity.
Fixing under-extrusion
Find out if gaps and weak layers come from asking for more flow than the nozzle can melt.
Comparing nozzles
See how a wider line or taller layer changes the flow before you slice.

How is the flow calculated?: Flow in mm³/s = line width × layer height × print speed. The cross-section is treated as a simple rectangle, which is a common approximation; real lines have rounded edges, so your slicer may show a slightly smaller number.
What is the filament feed rate?: It is the length of filament the extruder pushes per second: flow ÷ the area of the filament's circular cross-section (π × (diameter ÷ 2)²).
Where do I find my hotend's maximum flow?: Look at the manufacturer's specification, or test it: raise the speed until the extruder starts clicking or the lines turn thin. The limit depends on the hotend, the nozzle, the temperature and the filament, so treat published numbers as a starting point.