What This Calculator Tells You
Enter a spool price, the spool's gram weight, and how many grams your slicer says the print uses, and you get the material cost of that print. A 60 g print from a $25/kg spool costs 60 × $0.025 = $1.50 in filament; add a few cents of electricity and you have the true out-of-pocket cost. The Adjusted Cost field folds in your fail rate so a scrapped print is spread across the good ones, and Prints per Spool tells you how many copies one roll will make before you reorder.
Why Per-Gram Cost Beats a Guess
Spools are sold by the kilogram, but you print by the gram, and a spool almost never divides cleanly into whole parts. Reading the slicer's gram estimate and running it through the per-gram rate is the only way to know whether a print costs 40 cents or four dollars. That gap decides whether an Etsy listing makes money and whether a custom quote leaves you with margin after a failed first attempt.
Filament Is the Floor, Not the Price
The number here is your material cost — the floor. Selling prints means stacking electricity, machine wear, and your time on top. A printer pulling 120 W over a 5-hour job burns about 0.6 kWh, roughly 9 cents at $0.15/kWh, so power is minor; your labor and a sensible markup are what actually set the sticker price. Use this figure as the starting line, then build the quote up from there.
Filament Cost Calculator
How to Use This Calculator
- Enter the Spool Price and Weight: Type in what you paid for the spool and how many grams it holds — usually 1000 g for a 1 kg roll. Together these set your cost per gram, e.g. $25 ÷ 1000 = $0.025/g.
- Enter the Print Weight from Your Slicer: Slice the model in Cura, PrusaSlicer, or OrcaSlicer and copy the filament weight it reports into the Print Weight field. This already reflects your infill, walls, and supports.
- Set Your Fail Rate: Enter the share of prints you typically scrap — 2-5% once your printer is tuned, higher while you are still dialing in a new material. Leave it at 0 to see raw material cost only.
- Calculate and Read the Breakdown: Hit Calculate to see cost per gram, print cost, failure-adjusted cost, and prints per spool. Use the adjusted cost as your material floor when pricing a print for sale.
How It Works
The calculator turns a spool price into a per-gram rate, then multiplies by the grams your slicer reports for the print. A $25 spool holding 1000 g works out to $0.025 per gram, so a 50 g print costs 50 × $0.025 = $1.25 in raw filament.
The basic rule:
- Cost per Gram = Spool Price ÷ Spool Weight
- Print Cost = Cost per Gram × Print Weight
- Adjusted Cost = Print Cost × (1 + Fail Rate / 100)
- Prints per Spool = Spool Weight ÷ Print Weight (rounded down)
Filament is only the material line. If you sell prints, layer electricity, machine wear, and your own time on top of the adjusted cost before you set a price.
Tips & Considerations
- Take the Print Weight straight from your slicer's sliced-info panel — it already counts infill, walls, and supports, so you don't have to estimate.
- Set the Fail Rate to your honest average. At a 10% fail rate a $1.50 print really costs about $1.65 once you amortize the scrapped ones.
- Weigh a spool empty and full on a kitchen scale if you want an exact rate — the reachable filament is a bit less than the labeled kilogram.
- When choosing between PLA and PETG, slice the part in both and compare finished cost; the denser material can use more grams even at a similar spool price.
- For prints you sell, treat this figure as the floor, then add electricity (printer watts × hours ÷ 1000 × your $/kWh), machine wear, and your labor before markup.
Frequently Asked Questions
How do I find the grams of filament my print uses?
Slice the model first. Cura shows the filament weight and length in the bottom-right after slicing; PrusaSlicer and OrcaSlicer print it in the sliced-info panel, often with a dollar estimate if you entered your spool price. Use that gram figure directly in the Print Weight field — it already accounts for your infill, walls, and supports. If you only have the length in meters, roughly 3 g of 1.75 mm PLA equals about 1 meter.
Should I include electricity and failed prints in the cost?
For hobby prints, filament alone is close enough. If you sell or quote, add both. Electricity is small: a printer drawing 120 W for a 5-hour print uses 0.12 × 5 = 0.6 kWh, which at $0.15/kWh is about 9 cents. Failures matter more. Set the Fail Rate to your real average — 2-5% once you are dialed in, 10-20% while you are learning — so a scrapped print does not quietly eat your margin.
How do I price a 3D print to actually make a profit?
Start with the adjusted filament cost, then add electricity, a wear allowance for nozzles and belts, and pay yourself for design, slicing, and post-processing time. A common shop approach is to sum material plus machine time (often $1-$3 per printer-hour) plus labor, then apply a markup of 2-3× for retail. Example: a 60 g PLA print with $1.50 filament, 20 cents power, and 15 minutes of cleanup at $20/hour lands near $6.70 before markup.
How much does 3D printing filament cost per gram?
Most PLA runs $0.02-$0.03 per gram ($20-$30 per 1 kg spool). PETG is close at $0.022-$0.035/g. Flexible TPU, carbon-fiber blends, and polycarbonate climb to $0.04-$0.10 per gram. Plug your actual spool receipt into the calculator — sale-price and bulk spools can drop PLA below $0.02/g.
Does the printed weight match the spool weight I paid for?
Not quite. A '1 kg spool' means 1000 g of filament, but a small amount is unreachable — the last few grams near the empty core, plus purge and skirt on every print. In practice you get slightly fewer usable grams than the label. If you want to be exact, weigh the spool empty and full on a kitchen scale and use the net grams as your Spool Weight.
Should I compare PLA and PETG on price alone?
Price per gram gets you started, but the same model rarely weighs the same in both. PETG is a touch denser than PLA and often printed with thicker walls, so a part can use a few more grams. Slice the model in each material, read the gram figure from the slicer, and run both through the calculator. The cheaper spool per kilogram is not always the cheaper finished part.
How much filament does a typical 3D print use?
Small prints like keychains and minis use 5-20 grams. Medium prints such as phone stands and brackets use 30-80 grams. Large prints like vases and cosplay armor can hit 200-500+ grams. Your slicer reports the exact figure for your infill and wall settings before you commit to the print.
Which common filament is cheapest to print with?
PLA is usually the cheapest at $20-$30/kg and prints without an enclosure. PETG runs $22-$35/kg, ABS $20-$30/kg but needs heat containment, and TPU $25-$40/kg. Cheapest per kilogram is not always cheapest per part — a bulky PLA print can cost more filament than a small PETG one, so compare the finished-part cost the calculator gives you.