Filament Cost Calculator
Calculate the cost of 3D printing a model based on filament weight, spool price, and waste percentage.
About this calculator
This calculator turns a slicer's model-weight estimate into a real material cost. Filament Used (incl. waste) inflates Model Weight by Waste Percentage -- the material spent on supports, purge lines, skirts/brims, and the occasional failed print, expressed as a percentage of the model itself rather than a fixed gram amount, so a heavier print wastes proportionally more material too. Cost per Gram is simply Spool Price divided by Spool Weight, and Cost per Print multiplies that rate by Filament Used (incl. waste) -- so a cheaper spool, a lighter spool (fewer grams for the same price), and a smaller model or lower waste percentage all reduce Cost per Print, while a pricier or lighter spool raises it.
Prints per Spool floors Spool Weight divided by Filament Used (incl. waste) to a whole number, since a partial print's worth of leftover filament can't complete another full copy of the model. Spool Remaining After 1 Print is the simple subtraction of one print's usage from a full spool, useful for judging whether an open spool has enough left for one more run before you need a fresh one. None of these figures account for filament that degrades in storage, multi-color prints that waste material during color changes, or a printer's own mechanical purge requirements beyond the flat Waste Percentage you set.
Inputs
Results
Filament Used (incl. waste)
52.5 g
Cost per Print
$1.05
How to Use This Calculator
- Enter the model weight (g) from your slicer's estimated usage.
- Set the spool weight (g) and spool purchase price to calculate cost per gram.
- Enter your waste percentage to account for support material and purge lines.
- Review cost per print, total filament used including waste, and estimated prints per spool.
How the result changes with Model Weight
| Model Weight | Filament Used (incl. waste) | Cost per Print |
|---|---|---|
| 25 | 26.25 g | $0.53 |
| 38 | 39.9 g | $0.80 |
| 75 | 78.75 g | $1.58 |
| 125 | 131.25 g | $2.63 |
What each input means
- Model Weight
- Total weight of the printed model in grams (from slicer estimate).
- Spool Weight
- Net filament weight per spool (typically 1000g for a 1kg spool).
- Spool Price
- Purchase price for one spool of filament.
- Waste Percentage
- Estimated waste from supports, purge lines, skirts, and failed prints.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersModel Weight = 50, Spool Weight = 1000, Spool Price = 20, Waste Percentage = 5 = 4 input(s) provided
- Calculate Filament UsedFilament Used52.5 = 52.5
- Calculate Cost per PrintCost per Print1.05 = $1.05
- Calculate Prints per SpoolPrints per Spool19 = 19
- Calculate Waste per PrintWaste per Print2.5 = 2.5
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does a lighter spool cost more per gram than a heavier one at the same price?
Cost per Gram is Spool Price divided by Spool Weight, so at a fixed price a lighter spool spreads that price over fewer grams, raising the effective per-gram rate. This is why buying filament in bulk (larger spools) is usually cheaper per gram than smaller specialty spools sold at a similar or only slightly lower total price.
Does raising Waste Percentage change Cost per Gram?
No -- Waste Percentage only changes Filament Used (incl. waste), the total grams consumed by one print including supports and purge material; Cost per Gram depends solely on Spool Price and Spool Weight. Cost per Print still rises with Waste Percentage because it multiplies Cost per Gram by the now-larger Filament Used (incl. waste) figure, not because the material itself got pricier.
Why does Prints per Spool round down instead of showing a fraction?
A spool with, say, 2.7 prints' worth of filament remaining can only complete 2 full copies of the model before running out mid-print on the third -- there's no such thing as 70% of a finished print. Prints per Spool floors the division to the nearest whole number so it reports how many COMPLETE prints one spool guarantees, not a theoretical average.
If I switch to a heavier model, does Cost per Print scale exactly with the weight increase?
Very close to it, but not exactly, because Filament Used (incl. waste) applies Waste Percentage as a multiplier on Model Weight -- doubling Model Weight also doubles the waste grams alongside it, so Cost per Print scales almost linearly with Model Weight, with Waste Percentage along for the ride rather than staying fixed in absolute grams.
Does this calculator account for filament price changes between colors or materials?
No -- Spool Price and Spool Weight are whatever you enter for the specific spool you're costing out, so switching to a pricier specialty filament (carbon-fiber blends, flexible TPU, or dual-color spools) means re-entering that spool's own price and weight; the calculator has no built-in price table for different filament types.
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