If you sell printed parts, sooner or later someone will ask you how much filament does a 3D printer use, or you will wonder how many parts you get from one spool. The answer isn't a fixed number per hour: it depends on each part and how you set it up. Here is how to find the grams before you print, what makes a part use more, how far a kilo goes with hypothetical examples, and how to check it with a scale.
How much filament does a 3D printer use: per part, not per hour
A printer doesn't have a fixed filament use per hour. Two prints that take the same time can use very different amounts: a long hollow part uses little, and a compact block with high infill uses far more. That's why the right unit is grams per part, and you can know it before printing. Once you have the grams, material cost is grams times your price per gram, which you can work out with our guide to [PLA cost per gram](/en/blog/costo-por-gramo-pla).
Total filament a job consumes
The software works out the first part for you. The second part is yours: it comes from your experience and from keeping records. If you only charge for the grams of the finished part, you're giving away everything else.
How to find a part's grams in the slicer
Step 1: slice with your real settings
Use the same profile you'll print with: layer height, infill, walls, supports, and brim. If you change a setting later, the grams change too.
Step 2: read the slice summary
Most slicers show estimated filament in grams and meters, next to the print time. Write down the grams for each part or for the whole plate.
Step 3: confirm what that number includes
Check that it counts supports, brim, and purge tower if you use them. If you print several parts on one plate, divide the total by the number of parts to see each one's share.
That number is an estimate: very useful, but not perfect. It can come in a bit under reality because it can't see failures, extra purges, or the material lost when you change spools. That's what the scale is for, covered below.
What makes a part use more filament
Infill
The inside of the part. Raising the percentage or changing the pattern adds grams, and sometimes the extra strength is more than the customer needs.
Walls and solid layers
More walls and more top and bottom layers mean more material and more strength. Decide it based on what the part will be used for.
Supports
Printed to hold up overhangs and thrown away afterwards. They can weigh almost as much as the part itself. Changing the part's orientation sometimes cuts them down.
Brim or skirt
An extra outline that helps the part stick, or that primes the nozzle flow. It uses little per print, but it adds up if you print many small parts.
Purge tower
Shows up when you change color or material within a print. It's filament printed only to clean the nozzle, and on small multicolor parts it can weigh more than the part.
Test the same model with two settings
Slice the same part with lower infill and with higher infill, and compare the grams. In seconds you see what each decision costs in material, before spending a single real gram.
How far a kilo of filament goes: hypothetical examples
A 1 kg spool holds about 1,000 grams of filament. To find how many parts come from a kilo, divide 1,000 by the grams of each part. The table uses invented parts and a price of 20 USD per kilo purely as an assumption to show the math. Swap those numbers for your own.
Parts per kilo of filament (hypothetical examples, assumptions)
| Example part | Grams (slicer) | Parts per kilo (theoretical / with 5% waste) | Material at 20 USD/kg |
|---|---|---|---|
| Small keychain | 10 g | 100 / 95 | 0.20 USD |
| Phone stand | 25 g | 40 / 38 | 0.50 USD |
| Medium organizer | 80 g | 12 / 11 | 1.60 USD |
| Large part with high infill | 150 g | 6 / 6 | 3.00 USD |
| Very large part | 400 g | 2 / 2 | 8.00 USD |
Notice two things. First, only whole parts count: a kilo doesn't give you 12.5 organizers, it gives you 12. Second, the 5% waste is an example assumption, not a typical figure. You get your real percentage by weighing and recording, as the next section explains. To see how this cost feeds into the final price, read [how to quote 3D printing](/en/blog/como-cotizar-impresion-3d).
One useful detail: filament is bought by weight, but slicers also show meters. As a general reference, a 1 kg spool of 1.75 mm PLA holds roughly 330 meters, though it varies with material and diameter. For cost, what matters is the grams. And if you sell the same part many times, work out its real grams once and save them as a fixed figure, instead of re-slicing for every quote.
How to measure your real use with a scale
The slicer estimates. The scale confirms. A kitchen scale that reads to the gram is enough to calibrate your own math, and one that reads to a tenth of a gram is even better.
After a few weeks of data you'll know how far your slicer drifts from reality, and you can add a small allowance that's true to your shop. If you'd rather skip the manual math, the [free calculator](/en/calculator) works out material cost from the grams for you.
Frequently asked questions
How many grams of filament does a printer use per hour?+
How many parts come from one kilo of filament?+
Is the slicer always right about the grams?+
Should I charge for the filament in supports and purge?+
Let material with waste flow into the quote on its own
MiNegocio3D calculates the real cost of each part, including material with waste, electricity, machine wear, and time, so you don't have to remember every number. From 17 USD a month, with a 7-day free trial, no card required, and a 30-day guarantee.