3D Printing Water Calculator Formula
Learn how the calculator estimates water associated with filament, electricity, failed prints and post-processing.
This estimate combines water associated with the filament needed to complete a print, the electricity used while printing and any water used directly in finishing. It is useful for comparing print designs and settings with the same accounting factors.
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Estimated Total Water Use
Where:
First adjust filament and print time for expected failures. Then estimate water for filament and electricity, and add direct washing or rinsing water.
Variables Explained
| Variable | What It Means | Unit |
|---|---|---|
| W_total - Estimated total water use | Combined estimated water associated with one completed print. | litres |
| W_material - Filament-related water | Water estimated from adjusted filament mass and the selected filament water-use factor. | litres |
| W_electricity - Electricity-related water | Water estimated from electricity consumption and the selected electricity water-use factor. | litres |
| W_post - Post-processing water | Water directly used for washing, rinsing or finishing. | litres |
| f - Failed-print rate | Expected share of printing activity lost to failures, tests or reprints. | percent |
| m - Finished print weight | Weight of the successful finished print before the failure allowance. | weight |
| F_m - Filament water-use factor | Water associated with one kilogram of the selected filament. | litres per kg |
| P - Average printer power | Average power draw during printing. | watts |
| t - Print time | Print time for one successful print before the failure allowance. | hours |
| F_e - Electricity water-use factor | Water associated with one kilowatt-hour of electricity. | litres per kWh |
Step-by-Step Calculation
Calculate the successful-print rate
A 10% failed-print rate gives a 90% successful-print rate.
successRate = 1 - failedPrintRate / 100
Adjust filament for failures
Convert grams to kilograms, then increase the amount to allow for failed prints and reprints.
totalFilamentKg = printWeight / 1000 / successRate
Estimate filament-related water
Multiply adjusted filament mass by the selected material factor.
materialWater = totalFilamentKg * materialWaterFactor
Adjust printer time and calculate electricity
Convert watts to kilowatts and multiply by print hours adjusted for failures.
electricityKwh = printerPower / 1000 * printHours / successRate
Estimate electricity-related water
Multiply estimated electricity use by the local or chosen electricity factor.
electricityWater = electricityKwh * electricityWaterFactor
Add all water components
Add the material, electricity and direct post-processing estimates.
totalWaterUse = materialWater + electricityWater + postProcessingWater
Worked example: 150 g filament print
Successful-print rate
1 - 10 / 100
0.90
Adjusted filament
150 / 1000 / 0.90
0.167 kg
Filament-related water
0.167 * 20
3.33 litres
Electricity used
120 / 1000 * 8 / 0.90
1.07 kWh
Electricity-related water
1.07 * 1.5
1.60 litres
Total water use
3.33 + 1.60 + 0
4.93 litres
Final Result
Estimated total water use: about 4.9 litres.
Assumptions
- ✓Entered filament and electricity factors are appropriate lifecycle estimates for the comparison being made.
- ✓Failed prints consume filament and printer time at the same average rate as the successful print.
- ✓Post-processing water is entered as a direct amount and is not increased by the failed-print rate.
- ✓The same measurement approach is used when comparing multiple prints.
Limitations
- !Water factors can differ substantially by supplier, recycled content, production method, location and accounting method.
- !The estimate does not include printer manufacturing, packaging, transport or end-of-life handling.
- !Average printer power can differ from nameplate or peak power.
- !Direct water use may be difficult to measure where rinsing water is reused.
Common Mistakes to Avoid
Entering printer peak wattage instead of representative average power draw.
Using print weight that includes supports when the intended material estimate excludes them.
Entering a percentage as a decimal, such as 0.10 instead of 10, when the input expects percent.
Forgetting calibration prints, reprints or support failures when selecting the failed-print rate.
Comparing results based on water factors that use different boundaries or methods.
Related Formulas
Frequently Asked Questions
What is the formula for 3D printing water use?
The calculator adds filament-related water, electricity-related water and direct post-processing water after adjusting filament and print time for the failed-print rate.
Why is the finished print weight divided by the successful-print rate?
Dividing by the successful-print rate increases expected material use so it includes the filament lost in failures and reprints.
How is electricity use calculated for a 3D print?
Average power in watts is divided by 1,000 and multiplied by adjusted printing hours to produce kilowatt-hours.
Does a higher failed-print rate affect both material and energy?
Yes. It increases both total filament required and total printer hours in this model.
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