"How much does it cost per gram?" is one of the first questions every new print seller asks. It's a good place to start, but if you stop there, you'll underprice almost everything you sell.
Filament cost per gram
The simple part first. Divide the spool price by its weight in grams:
Cost per gram = spool price ÷ spool weight (g)
| Spool | Price | Cost per gram |
|---|---|---|
| Standard PLA, 1 kg | $25 | 2.5¢ |
| PETG, 1 kg | $30 | 3.0¢ |
| Specialty (silk, carbon fibre), 1 kg | $45 | 4.5¢ |
| PLA, 750 g | $22 | 2.9¢ |
Example prices only.
Watch the spool size. A cheaper spool with less filament on it can cost more per gram.
Then add a waste allowance (often around 10%) for purge, supports, brims, and the last bit on the spool. A 120 g print really uses about 132 g of what you paid for.
Why cost per gram isn't the whole story
Filament is a material cost. But a print also uses time: machine time and your time. Every hour a printer runs, it uses electricity, wears out, needs maintenance, and carries a share of your shop's overhead.
Using the same example shop as our pricing guide, those hourly costs add up to about $0.43 per print hour, plus your hands-on time.
For a 120 g plate that prints in 6 hours, the fully loaded cost was $10.52. That's about 8.8¢ per gram, compared with 2.5¢ for the filament alone. The real cost per gram was more than three times the filament price.
Same weight, different cost
Here's why a single "per gram" price doesn't work. Two prints, both 120 g of the same PLA:
| Solid block | Tall vase | |
|---|---|---|
| Filament | 120 g | 120 g |
| Print time | 3 hours | 10 hours |
| Fully loaded cost | $9.18 | $12.31 |
| Real cost per gram | 7.7¢ | 10.3¢ |
Same example rates as the pricing guide: 10 minutes of labour, 5% failed-print reserve.
The vase takes more than three times as long to print, so it costs more to make, even though it weighs the same. Charge both at one per-gram rate and the vase quietly eats your profit.
When pricing per gram is fine
Some shops quote by the gram for simple jobs, and that's fine as a quick estimate if:
- your per-gram rate is based on your real cost per gram, not the filament price
- you add a time charge for slow prints (tall, detailed, or small-nozzle jobs)
- you have a minimum charge for small prints
The better approach
Cost each product using both its grams and its print time, then set your price from a target margin. Our complete guide to pricing 3D prints walks through it step by step.
Or try the free 3D print cost calculator: enter the grams and print time from your slicer and see the real cost in a minute.