What does one print actually cost?
Filament, electricity, printer wear and the prints that fail, per part and per batch. Drop in an STL if you have not sliced it yet. Free, no card.
Where the money goes
On most small prints the filament is the smallest line people think about and the only one they count. A 60 g part in 20-a-kilo PLA is 1.20 of plastic. Three hours on a 600 printer you expect 5,000 hours from adds another 0.51 in wear and upkeep, the electricity is about 6 cents, and if one plate in ten fails you pay for the lot again a tenth of the time. That is how a "1.20 part" becomes a 2-and-something part before you have touched it.
Then there is your time. Clearing the plate, pulling supports and sanding a seam is ten minutes per plate on a good day. The rate field is zero by default so the figure starts as a floor, but if you sell what you print, put a real number in it: it is usually the largest cost of the lot.
Printing a mold instead?
If the print is a mold you will cast into, the print is a one-off and the cost that matters is per cast. Put this calculator's answer into the casting cost calculator as the mold cost, and it spreads it over every piece you pour. The silicone calculator covers the silicone half of a mold.
Questions
How do I calculate the cost of a 3D print?
Add four things: the filament (grams from your slicer times your price per kilogram), the electricity (average watts times print hours times your price per kWh), printer wear (the printer's price divided by the hours you expect from it, plus spare parts per hour) and failed prints (the same three again for every plate you throw away). Divide by the number of parts on the plate, then add any per-part extras like magnets or a bag.
How much electricity does a 3D printer use?
Less than its power supply rating suggests. A current enclosed or bedslinger printer averages roughly 100 to 150 W while printing PLA, most of it the heated bed, so a 5 hour print uses well under 1 kWh. ABS and ASA with a hot bed and a heated chamber run higher.
How do failed prints change the cost?
A failed plate burns filament, power and machine hours and produces nothing, so with a failure rate f you need 1 / (1 - f) attempts per good plate. At 10% that adds 11% to the machine cost, at 25% it adds a third. Your post-processing time and per-part extras are not repeated, which is why the calculator charges failures on the plate only.
How accurate is the STL estimate?
Within about 20% for an ordinary part. It reads the model's volume and surface area, assumes a 1.2 mm solid shell plus your infill inside it, and times it at 2 minutes per gram, the same rate we use for the print times in the free mold files. Supports, brims and very thin walls are not counted. Your slicer's figure is always better, so type it in once you have one. The file never leaves your browser.
Can I sell what I print from Meshcast files?
Yes, with Pro or Founder, which include commercial rights. Free use is personal only. The licence page spells out what each plan covers.