FDM Print Time by Volume and Speed

Estimating 3D print time from volume and nozzle speed

A rough first cut at FDM print duration leans on the volumetric flow rate: t ≈ volume / (v · A_extrusion). Here v is the nozzle travel speed in mm/s, and A_extrusion is the cross-section of the extruded line, which works out to about A ≈ nozzle_diameter · layer_height. Take a 0.4 mm nozzle laying 0.2 mm layers at 60 mm/s: that’s a throughput of roughly 0.4 · 0.2 · 60 = 4.8 mm³/s. For comparison, modern hotends like the Bambu Lab P1S or the Voron Stealthburner push 25–60 mm³/s once you fit a high-flow nozzle.

A 100×100×50 mm part (a 500 cm³ bounding box) at 20% infill usually runs 5–10 hours on a stock Ender 3. Tune the same job on a Klipper machine with input shaping and pressure advance and you’re looking at 1–3 hours. Slicers like PrusaSlicer, OrcaSlicer, Cura and Bambu Studio work out the real toolpath time, acceleration, travel moves, per-layer Z-hop and all, so treat this formula as a sanity-check you run before slicing.

Applications

Think quoting print-on-demand jobs, scheduling overnight runs on a print farm, weighing PLA against PETG and ABS throughput, choosing a 0.4 mm or 0.6 mm nozzle for a big prototype, or working out filament cost per minute of machine time. On infill-heavy parts, Klipper’s acceleration tuning, resonance compensation and high-flow CHT-style nozzles can take a 10 h print down to 3 h and still leave the surface clean.

FAQ

Why does my slicer report a longer time than this calculator? The formula skips travel moves, retractions, acceleration ramps, layer-change pauses and the slower speed on the outer perimeter. Your slicer simulates the actual G-code, so its number tends to land 20–50% higher.

Does infill percentage matter? It does. The volume you feed the formula should be the plastic actually extruded, not the bounding box. A 100 cm³ cube at 20% infill with 3 perimeters only puts down something like 30–40 cm³ of plastic.

How do I increase volumetric flow? Go to a wider nozzle (0.6–0.8 mm), fit a high-flow hotend (Bambu, Revo HF, Volcano), bump the nozzle temperature by 10–15 °C, and turn on input shaping so the higher acceleration doesn’t leave ringing on the surface.