Filament Cost Calculator
Calculates the exact material cost for a 3D print by comparing filament used to total spool weight. Use it before or after a print to track spending and compare materials.
About this calculator
The cost of a 3D print depends on what fraction of a filament spool you consume. The formula is: cost = (filament_weight / spool_weight) × spool_cost. This works because filament is sold by weight, so dividing the grams used by the total spool weight gives you the proportion consumed. Multiplying that proportion by the full spool price yields the actual material cost. For example, using 10% of a spool means paying 10% of the spool's price. This approach works for any filament type — PLA, ABS, PETG, TPU — as long as you use consistent weight units throughout. Slicers like Cura or PrusaSlicer report filament weight directly, making this calculation straightforward after slicing.
How to use
Suppose your slicer reports a print will use 45 g of filament. Your spool weighs 1,000 g and cost $22. Plug in the numbers: cost = (45 / 1000) × $22 = 0.045 × $22 = $0.99. Your print material costs just under a dollar. If you run multiple prints from the same spool, repeat the calculation for each job and sum the results to track total spool spend accurately.
Frequently asked questions
How do I find the filament weight used for a specific 3D print?
Most slicing software — including Cura, PrusaSlicer, and Bambu Studio — displays estimated filament usage in grams after you slice your model. Look for the print summary panel before you export the file to your printer. If your slicer only shows length in meters, multiply by the filament's linear density (g/m), which you can find on the manufacturer's spool label or datasheet. Weighing the spool before and after printing on a kitchen scale is the most accurate real-world method.
Why does the filament cost calculation use spool weight instead of spool length?
Weight is a more reliable measure than length because filament diameter can vary slightly along the spool, and different materials have different densities — a meter of nylon weighs less than a meter of PETG at the same diameter. Slicers typically report usage in grams because it accounts for these variations automatically. Using weight keeps the proportion calculation consistent regardless of material type or filament brand. Always make sure your spool weight refers to the net filament weight, not the weight including the spool itself.
What is a typical filament cost per gram for PLA in 2024?
A standard 1 kg PLA spool typically costs between $18 and $28 USD from mainstream brands, putting the per-gram cost at roughly $0.018–$0.028. Budget spools can go as low as $15, while premium or specialty colors may exceed $35. High-performance materials like carbon-fiber-filled PLA or flexible TPU can cost $40–$80 per kilogram. Calculating per-print cost with this calculator helps you understand whether switching to a cheaper spool brand meaningfully changes your production costs.