Filament cost calculator

A slicer will happily tell you a print weighs 34 grams and then leave you to work out whether that is worth doing. It usually is: at typical spool prices a part like that costs less than a coffee, and the thing people actually get wrong is the direction of the surprise — small prints are cheaper than they feel and long ones cost more, because a printer left running for two days is a small heater with a motor in it. This page takes the price you paid for the spool, the weight of filament on it and the weight the slicer quotes, and turns them into what the print costs. If you also know what the printer draws and how long it will run, it adds the electricity at whatever your bill charges. It ships no filament price and no tariff of its own, because both move by country and by month.

How it is calculated

filament = price × print weight ÷ spool weight · electricity = W × h ÷ 1000 × price per kWh

The filament half is a proportion: you bought a spool for a price, the print takes a share of that spool by weight, and it costs the same share of the price. The electricity half is the same arithmetic every appliance uses — watts times hours divided by a thousand gives kilowatt hours, and kilowatt hours times your price per unit gives money. The two are added, not blended, so you can see which one is actually driving the cost of a long print.

Source: A print uses a share of the spool, so it costs the spool price times that share — the whole spool costs the whole price and half of it costs half

Questions people ask

Should the spool weight be 1000 g?

Only if that is what you bought. A one-kilogram spool holds a kilogram of filament and the reel it is wound on is extra, so 1000 g is the right number for the field — but it is not the only size on the shelf. UltiMaker's Method sheets give a net filament weight of 650 g, BCN3D's give 750 g, and half-kilo spools are everywhere. Using 1000 when the spool holds 750 understates every print by a quarter, and that is a much larger error than anything else on this page.

What does my printer actually draw?

Less than the rating on its power supply, and there is no published figure that would tell you how much less. The heated bed is most of the load and it cycles on and off once it reaches temperature, so the average over a print is nothing like the peak the supply is sized for. If you want a number you can trust, put a plug-in energy meter between the printer and the wall and read the kilowatt hours off it after a real print. Leaving this field at zero prices the filament alone, which is the honest default when you do not know.

Why is there no filament price built in?

Because there is no such thing as the filament price. The same PLA sells at very different figures in different countries, brands span a factor of three, and the number would be stale within months of being written. The receipt in your inbox is the only price that answers your question, and it is one field to type.

Does this include failed prints and purge?

No, and that is worth knowing when you compare the answer to your actual spending. The slicer's figure covers the part and its supports; it does not cover the skirt, the purge tower on a multi-material print, the length wasted at every filament change, or the three attempts before the one that stuck. If you are budgeting rather than costing a single object, adding a margin on top of this number is closer to the truth than the number itself.

What about wear on the machine?

It is real and it is not here. Nozzles wear, especially on filled filaments, belts and bearings have lives, and a build plate eventually stops holding. None of that has a published figure that would survive being written into a page — it depends on the machine, the materials and how hard you run it. What this page gives you is the cost that changes with the print itself: plastic and power.

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