Enter the filament used, average flow rate, and optional overhead into the calculator to estimate the 3-D print time. For advanced estimates, upload an ASCII STL file and provide layer height, infill, and build speed parameters.

3-D Print Time Formula

This calculator estimates how long a 3-D print will take using either a quick material-based method or an STL-based planning method. Use the simple mode when you already know the part’s filament usage in grams. Use the STL mode when you want to start from model geometry and adjust the estimate with layer height, infill, and build speed.

Simple Estimate Formula

T_{min} = 60 \times \frac{F}{R} + O
  • Tmin = estimated total print time in minutes
  • F = filament used for the part, in grams
  • R = average flow rate, in grams per hour
  • O = fixed overhead, in minutes

If you want the final estimate in hours, convert minutes to hours with:

T_{hr} = \frac{T_{min}}{60}

How the STL Estimate Works

In STL mode, the calculator reads the model volume from an uploaded ASCII STL file and uses that volume as the basis for a time estimate. The result is then shaped by the settings that most strongly affect print duration:

  • Lower layer height increases the number of layers and usually increases total time.
  • Higher infill percentage increases internal material and usually increases total time.
  • Higher build speed reduces time only if your printer, filament, and hotend can sustain that throughput.

If your slicer shows speed in millimeters per second but the calculator expects millimeters per minute, convert it first:

B_{mm/min} = 60 \times B_{mm/s}

Input Reference

Input What to Enter Why It Matters
Filament Used The estimated material consumption for the part, in grams More material generally means more extrusion time.
Average Flow Rate Your printer’s realistic material throughput, in g/hour This is the main speed term in simple mode. Higher flow rate lowers time.
Overhead Minutes for bed heating, homing, probing, purge lines, tool changes, or pauses Overhead is added directly to the estimate and matters most on short prints.
STL File An ASCII STL model file The calculator uses the mesh to derive model volume.
Layer Height The planned layer thickness in mm Smaller layers improve detail but increase layer count and print time.
Infill Percentage The intended internal fill density Higher infill adds internal paths, weight, and time.
Build Speed The print speed in mm/min Higher speed can shorten time, but only within stable print limits.

How to Use the Calculator

  1. Choose the method. Pick Simple if you know the filament mass. Pick STL if you want to estimate from the 3-D model file.
  2. Enter realistic printer settings. Use values you can actually sustain, not just the highest speed shown in firmware or slicer profiles.
  3. Add overhead. Short jobs are often underestimated when warmup and setup time are ignored.
  4. Compare the result to slicer output. If your slicer estimate is much longer, the difference is usually caused by travel moves, retractions, acceleration limits, supports, or slow outer walls.

Example

Suppose a print uses 120 g of filament, your average flow rate is 24 g/hour, and setup overhead is 12 minutes.

T_{min} = 60 \times \frac{120}{24} + 12
T_{min} = 312
T_{hr} = \frac{312}{60} = 5.2

The estimated print time is 312 minutes, which is 5.2 hours.

What Changes Print Time the Most

Adjustment Effect on Time Typical Trade-Off
Decrease layer height Longer print Better surface finish and finer detail
Increase infill percentage Longer print Higher part weight and internal strength
Increase build speed Shorter print Can reduce quality if cooling, extrusion, or motion control cannot keep up
Add supports Longer print Improves success on overhangs but adds extra material and removal time
Increase wall count or top/bottom layers Longer print Improves strength and surface closure
Use a larger nozzle and thicker layers Shorter print Faster output with less fine detail

Why Actual Print Time May Differ

A calculator gives a planning estimate, not a full motion simulation. Real print time can run higher or lower depending on:

  • travel moves between separate islands or features
  • retractions and z-hop behavior
  • firmware acceleration and deceleration limits
  • slow first layers and reduced outer-wall speeds
  • support structures and brim or raft usage
  • cooling slowdowns on small layers
  • multi-color or multi-tool changes
  • pause commands, camera timelapses, or manual interventions

Common Input Mistakes

  • Entering mm/s instead of mm/min. This makes STL-mode speed values too small by a factor of 60.
  • Using spool weight instead of part weight. Only the material consumed by the print should be entered.
  • Ignoring overhead. Warmup and calibration can be a meaningful share of total time on smaller jobs.
  • Uploading the wrong STL format. The advanced mode expects an ASCII STL file.
  • Assuming the estimate includes post-processing. Sanding, curing, cooling, support removal, and assembly are separate time costs.

Choosing the Right Estimation Method

Use Simple mode when your slicer already reports filament usage in grams and you only need a fast time estimate. Use STL mode when you are comparing design options early, do not have a full slice yet, or want a quick estimate from geometry plus a few key settings.

Practical Tip

If you already have both a slicer time estimate and the calculator result, the slicer is usually better for final scheduling, while the calculator is better for early planning, quoting, and comparing how changes in layer height, infill, speed, or material usage will affect the job.