Nozzle Flow Rate Calculator
Calculate volumetric flow rate through your 3D printer nozzle from diameter, layer height, and speed.
Identify your max flow rate to prevent under-extrusion.
Volumetric flow rate describes how much plastic a 3D printer extruder pushes through the nozzle per second. It is the key limit that determines how fast you can print reliably without under-extrusion.
Flow rate formula: Volumetric Flow (mm³/s) = Layer Height × Line Width × Print Speed
Where:
- Layer Height is in mm (e.g., 0.2 mm)
- Line Width is in mm (typically 100–120% of nozzle diameter)
- Print Speed is in mm/s
Worked example: Layer height: 0.2 mm | Line width: 0.4 mm | Print speed: 60 mm/s Flow Rate = 0.2 × 0.4 × 60 = 4.8 mm³/s
Maximum flow limits by nozzle size (standard brass, PLA):
- 0.2 mm nozzle: ~3–5 mm³/s
- 0.4 mm nozzle: ~8–12 mm³/s
- 0.6 mm nozzle: ~15–20 mm³/s
- 0.8 mm nozzle: ~25–35 mm³/s
These limits are higher with hardened steel or ruby nozzles, and higher still with high-flow hotends like the Volcano or Dragon HF.
Why this matters: If your slicer-calculated flow rate exceeds the nozzle’s physical limit, the filament cannot melt fast enough. The result is under-extrusion — gaps, weak layer bonding, and failed prints. Always calculate your flow before pushing speed.
Pressure advance / linear advance: At high flow rates, molten plastic in the nozzle compresses slightly. Firmware features like Pressure Advance (Klipper) or Linear Advance (Marlin) compensate for this by adjusting extruder speed during acceleration and deceleration — improving corner quality at speed.