3D Print Time Estimator

The print time (in hours) is estimated by dividing the total filament weight (in grams) by the printer's throughput (in grams per hour). Mathematically: Time (hours) = Filament Weight (g) / Throughput (g/hr). Filament weight is the mass of plastic required for the object, which you can obtain from your slicer's material estimate or by calculating from volume (mm³) times filament density (typically 1.24 g/cm³ for PLA). Throughput is the product of your printer's layer height (mm), line width (mm), print speed (mm/s), and the number of active extruders, converted to grams per hour via the filament density: Throughput (g/hr) = Layer Height (mm) * Line Width (mm) * Print Speed (mm/s) * 3600 (s/hr) * Density (g/mm³) * Number of Extruders. Density in g/mm³ is 0.00124 for PLA. This formula assumes continuous, uninterrupted extrusion at a constant speed, ignoring acceleration, retraction, and non-printing moves. It provides a quick sanity check because slicers account for these inefficiencies, so your estimate will be lower than the slicer's actual time. Use it to catch gross errors, like a part that would take 50 hours when you only have 10.

This estimate is a lower bound—your actual print time will always be higher because slicers include acceleration, retraction, travel moves, and non-printing operations. A good rule of thumb: your slicer's time is typically 20–50% longer than this raw calculation. If your estimate is less than half the slicer's time, you likely have a setting error (e.g., wrong filament density or speed). Conversely, if your estimate exceeds the slicer's time, check your math or slicer settings—this is rare and may indicate a mistake. For typical FDM printers with PLA, throughput ranges from 10–30 g/hr for fine detail prints (0.1 mm layers, 40 mm/s) to 50–100 g/hr for draft prints (0.3 mm layers, 100 mm/s). Use this tool to quickly assess if a print is feasible within your time budget before investing in slicing. It is not a replacement for slicer estimates, but a gut check for large or time-sensitive projects.

Common mistakes: (1) Using slicer-reported time as a direct comparison—remember this estimate is a lower bound. (2) Forgetting to adjust filament density for materials like PLA (1.24), ABS (1.04), PETG (1.27), or flexible filaments (1.20–1.25). (3) Ignoring multi-extruder setups—throughput should be summed only for simultaneous printing, not sequential. (4) Using average print speed instead of actual print speed—acceleration and jerk settings reduce effective speed. (5) Assuming constant throughput—overhangs, bridges, and small details slow down printing. Edge cases: very small parts (under 5 grams) have high relative error due to retraction time; very large parts may be limited by max flow rate of your hotend, which caps throughput. Always verify with your slicer.

Throughput

The rate at which a 3D printer extrudes filament, measured in grams per hour, calculated from layer height, line width, speed, and filament density.

Filament Density

The mass per volume of the filament material, typically 1.24 g/cm³ for PLA, used to convert volumetric flow to mass flow.

Layer Height

The vertical thickness of each printed layer, usually in millimeters, directly affecting print resolution and speed.

Line Width

The horizontal width of the extruded plastic bead, typically 0.4 mm for a 0.4 mm nozzle, influencing throughput and part strength.

Print Speed

The velocity of the print head during extrusion, measured in mm/s, a key factor in throughput calculation.