Guide · 8 min read · free tool
3D Printing Cost: Filament, Hours, and the Electricity You Pretend Is Free
Sep 8, 2026 · Zelpura Editorial · All guides
A 3D print looks almost free because the machine is already on the desk. The spool was bought last month, the electricity is a rounding error in your head, and your evening does not have a rate. A buyer does not care about that story. A price has to cover plastic, power, failures, and the time you will not get back. This page takes grams of filament, price per kilogram, print hours, and watts, so the physical cost is visible. It will not type your hourly rate. You should, on a sticky note, next to the result, or you will sell a six-hour print for the cost of the plastic and call it a shop.
The inputs are the job, not a formality. Filament used is the slicer's estimate plus a scrap allowance, not the optimistic number from a preview you have not printed. Price per kilogram is what you paid for that material, including shipping if the spool was a special order. Hours are print time, not design time. Watts are the printer's draw while printing. Electricity on this page is priced at a fixed 15 cents per kilowatt-hour, not a rate you type. The total also adds 10 cents an hour of machine wear, even if your eye stays on the filament line. Design time and failed prints are still absent. Add those in your head or you will underprice.
A part that uses 80 grams of filament at 25 dollars a kilogram is 2 dollars of plastic. Ten hours at 120 watts is 1.2 kilowatt-hours. At the page's fixed 15 cents, electricity is about 18 cents, and the built-in wear line is another dollar. The on-page total is a little over 3 dollars, not 2. If one print in four fails and you lose the plastic, load another 50 cents or so of expected waste. If your time is worth 20 dollars an hour and you spend 30 minutes on setup and post-processing, that is 10 dollars. The honest price starts near 13 dollars before profit, not near 2. People who sell at 5 dollars are buying a hobby and calling it revenue. Hobbies are allowed. Invoices should say so.
The miss is quoting the slicer's plastic cost as the price. The second miss is ignoring failures. A beautiful settings profile still fails, and the failed grams were real. The third miss is forgetting that a printer tied up for ten hours cannot print the other job. Capacity is a cost when you have a queue. It is not a cost when the machine would have sat idle. Be honest about which week you are in. Also separate prototype grams from production grams. The first version's waste should not be hidden inside the unit cost of the tenth, or the tenth will look mysteriously expensive and you will 'optimize' a price that was actually a learning curve.
Slice the part, read the grams and the hours, and type them. Use the spool price you paid. Read the electricity line so you can stop claiming it is zero, and also stop claiming it is the main cost. It is usually neither. Then write your time underneath the result, by hand. Add a failure rate you have earned, not a failure rate you hope to have after you fix the first layer. Quote the sum plus a margin, or decide it is a gift. Gifts are fine. Accidental gifts are how small print shops die while looking busy.
This is a cost sketch, not a quote for a certified part. Printed plastic is not automatically food-safe, heat-safe, or strong enough for a load someone could get hurt by. Nothing here is engineering advice. Electricity rates and spool prices move. A watt figure you guessed will move the electricity line a little and the decision almost not at all, which is useful to know. Do not use a low plastic cost to justify a part that should have been bought as hardware. Sometimes a screw from a shop is the correct manufacturing process. The printer does not need to win every object.
Log five prints: estimated grams, actual grams if you weighed them, hours, failures. The ratio of estimate to reality is your personal fudge factor. Type it next time by adding grams, not by hoping. When you raise prices, you will have a log instead of a feeling. Customers can argue with a feeling. They can also see a breakdown. Offer the breakdown. A maker who can say 'plastic, power, time, failure reserve' sounds like a shop. A maker who says 'it's just a print' sounds like a discount.
Read the result back before you act. Say plastic, power, and time as three numbers. If you only say plastic, you are about to donate the evening. The evening was the expensive input.
Wear on the machine — nozzles, belts, a sheet — belongs as a few cents to a dollar on a long print, not as zero. You do not need a depreciation schedule to stop pretending the machine is immortal. Add a small reserve. If the reserve annoys you, you are attached to the two-dollar story. Let it go. The spool will not be offended, and your future self will buy the next nozzle without resentment.
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