How the cost of a 3D print is worked out
The true cost of one print is the sum of these lines:
- Filament: spool price divided by spool weight gives the cost per gram, times the grams the slicer reports. A $18.99 spool of 1,000 g is $0.01899 a gram, so 162 g costs $3.08. Rounding the per-gram cost to two cents first would make it $3.24, an error that repeats on every print.
- Printer wear: what the printer cost, plus the nozzles, belts and plates it will use up, spread over the hours it will run. That gives a cost per hour, times the print time.
- Electricity: average watts divided by 1,000, times print hours, times your price per kWh.
- Your time: hands-on minutes for removal, supports and finishing, at the hourly rate you pay yourself. One-off design time is spread across the batch rather than charged to every print.
- Failure allowance: a percentage added to the filament, printer wear and power, because a failed print burns those even though it never sells.
- Hardware and packaging: magnets, inserts, boxes, added per item.
Margin is not markup
Margin is profit as a share of the sale price. Markup is profit as a share of the cost. A 50% margin is a 100% markup: a print that costs $10 sells for $20. The suggested prices here are margins, and the calculator shows both figures for your price so they can't be confused.
Why the price is solved, not marked up
Marketplace and payment fees are a percentage of the sale price, the number you are trying to find. Adding a markup and then subtracting the fees misses your target every time. The calculator solves it directly: price = (cost + fixed fee) ÷ (1 − margin − fee percentage). When the margin and fees together reach 100% of the sale, no price works, and it says so instead of giving you a number that loses money.
Profit per print hour
Two prints with the same profit aren't worth the same if one keeps the printer busy twice as long. Profit per print hour tells you which products earn the most for the machine time they take.