3D Printing Efficiency Formula
Learn how 3D printing efficiency is calculated from model material, non-model material, expected failures and job time.
This formula estimates the share of filament that remains in the completed model after supports, purge material and expected reprints are included. It also estimates total material use and job time per completed model, helping you compare slicing and print-planning choices.
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Material Efficiency
Where:
Add all material used in one print attempt, increase it to allow for expected failed attempts, then divide the finished model's material by that expected total.
Variables Explained
| Variable | What It Means | Unit |
|---|---|---|
| modelMaterial - Model material | Filament retained in the finished model, excluding supports, brims, rafts and purge material. | g |
| supportMaterial - Support material | Estimated filament used for supports, rafts, brims and similar removable features. | g |
| purgeMaterial - Purge and priming material | Estimated filament used for priming, purge towers, color changes and other non-model extrusion. | g |
| failureRate - Expected print failure rate | The percentage of print attempts expected to fail and require another attempt. | percent |
| printHours - Successful print time | Slicer-estimated machine time for one successful print attempt. | hours |
| setupHours - Setup and post-processing time | One-time preparation and finishing time allocated to the completed model. | hours |
Step-by-Step Calculation
Calculate material for one print attempt
This includes all filament consumed in a normal attempt, whether or not it remains in the model.
baseMaterial = modelMaterial + supportMaterial + purgeMaterial
Allow for expected failed attempts
Dividing by the expected success rate estimates average material consumption for one completed model.
expectedTotalMaterial = baseMaterial / (1 - failureRate / 100)
Calculate material waste
Waste is all expected material that does not remain in the finished model, including non-model material and failed attempts.
materialWaste = expectedTotalMaterial - modelMaterial
Calculate material efficiency
This is the percentage of expected filament consumption retained in the final model.
materialEfficiency = (modelMaterial / expectedTotalMaterial) * 100
Calculate expected machine print time
The same success-rate adjustment increases machine time to account for likely reprints.
expectedPrintHours = printHours / (1 - failureRate / 100)
Calculate total job time and time efficiency
Total time includes expected machine time plus setup and post-processing. Time efficiency is the successful print time as a share of that total.
expectedTotalHours = expectedPrintHours + setupHours; timeEfficiency = (printHours / expectedTotalHours) * 100
Worked example: functional print with supports
Material per attempt
80 + 15 + 5
100 g
Expected total material
100 / (1 - 10 / 100)
111.1 g
Expected material waste
111.1 - 80
31.1 g
Material efficiency
(80 / 111.1) × 100
72.0%
Expected total job time
8 / 0.90 + 0.5
9.4 hours
Time efficiency
(8 / 9.4) × 100
85.2%
Final Result
The completed 80 g model is estimated to require 111.1 g of filament and 9.4 hours in total, with 72.0% material efficiency and 85.2% time efficiency.
Assumptions
- ✓The failure rate represents repeated attempts with similar settings, geometry and material.
- ✓A failed attempt is assumed to consume the same average material and machine time as a successful attempt.
- ✓Supports, purge material and other non-model extrusion are included in the estimates provided.
- ✓Setup and post-processing time is treated as a one-time amount per completed model.
- ✓The calculation measures material and time efficiency, not monetary cost or environmental impact.
Limitations
- !Real failed prints may stop early or fail late, so their material and time use can differ substantially from a full attempt.
- !Slicer estimates can differ from actual extrusion because of calibration, flow variation, filament condition and printer behavior.
- !Multi-part batches may share setup time, so a per-model result can be different for a production run.
- !The calculation does not include electricity, maintenance, depreciation, labor cost or material storage losses.
Common Mistakes to Avoid
Entering the model-only filament weight as the total slicer material estimate.
Leaving brims, rafts or purge towers out of support and purge material.
Using a failure rate of 10 instead of 10% in a spreadsheet formula that expects a decimal.
Treating setup time as machine printing time when comparing printer utilization.
Assuming a failed print always uses a full print's worth of material and time without reviewing print history.
Related Formulas
Frequently Asked Questions
What is the formula for 3D printing material efficiency?
Material efficiency equals model material divided by expected total material, multiplied by 100. Expected total material includes supports, purge material and an allowance for failed attempts.
Why divide by one minus the failure rate?
One minus the failure rate is the expected success rate. Dividing material or machine time by that rate estimates the average resources needed to achieve one completed print.
How is 3D printing waste calculated?
Expected material waste is expected total material minus the model material. It includes removable print features and expected material lost in failed attempts.
Does a 0% failure rate remove the reprint allowance?
Yes. At a 0% failure rate, expected total material equals the material used in one print attempt and expected machine time equals the slicer print time.
Can material efficiency be higher than 100%?
No. With non-negative support and purge material and a valid failure rate, the model cannot use more material than the expected total consumed.
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