🌊 Volumetric Flow Rate Calculator
Enter your layer height, line width and print speed to get the volumetric flow — and check it against your hotend's maximum.
Required volumetric flow
6.4 mm³/s
Max speed at this line
150 mm/s
Volumetric flow = layer height × line width × speed — the plastic your hotend must melt each second. A standard hotend manages roughly 10–15 mm³/s; high-flow / Volcano-style hotends reach 20–40+. If your required flow tops your hotend's limit, the print under-extrudes no matter what the speed says. 🔒 In your browser.
How the volumetric flow rate calculator works
Volumetric flow is the amount of plastic your hotend has to melt each second: layer height × line width × print speed, in mm³/s. Every hotend has a maximum flow it can melt fast enough; ask for more and the print under-extrudes no matter what speed the slicer shows. The tool computes the required flow, flags it if it exceeds the hotend limit you enter, and shows the fastest print speed that limit allows for your line.
A standard hotend manages roughly 10–15 mm³/s; high-flow or Volcano-style hotends reach 20–40 mm³/s or more. The real limit depends on the material and temperature, so treat these as guidelines and, for a precise figure, run a max-flow test on your own printer.
Frequently asked questions
What is volumetric flow rate in 3D printing?
The volume of plastic extruded per second: layer height × line width × print speed, in mm³/s. It's the true speed limit of a hotend, because it can only melt filament so fast regardless of how quickly the nozzle moves.
How fast can I print without under-extruding?
Until the required volumetric flow reaches your hotend's maximum. For a 0.2 mm layer and 0.4 mm line, a 15 mm³/s hotend allows up to about 187 mm/s; beyond that it can't melt filament fast enough.
What is the max volumetric flow of a hotend?
Roughly 10–15 mm³/s for a standard hotend and 20–40+ mm³/s for high-flow/Volcano designs, but it varies with material and temperature. Run a max-flow calibration test to find your exact limit.
Why is my print under-extruding at high speed?
Likely because the required volumetric flow exceeds what your hotend can melt. Slow down, use a thinner layer or narrower line width to lower the flow, print hotter (within the filament's range), or fit a high-flow hotend.
How do I increase my printing speed?
Raise the flow ceiling: a higher-flow hotend, a higher (safe) temperature, or a thicker layer/wider line, which lets each pass lay down more plastic. The volumetric limit — not the motion speed — is usually what caps real throughput.