3D Printing Cost Calculator FAQ
Every input in SpoolTrak, the free 3D printing cost calculator, explained in plain language — how filament, electricity, printer depreciation, and labor add up to a unit cost, and how the spreadsheet exports work.
Project Details
Project name
Label for the print job — appears in the cost summary and lets you keep prints organized.
Print time (h / m)
Total slicer-estimated printing time. Used for electricity, depreciation, and AMS calculations.
Design time
Minutes spent modeling, setting up the slice, or test-printing — before the final print starts. Multiplied by its own hourly rate, charged in full to this project (not spread across future reprints).
Design hourly rate
Your rate for design work in $/hour. Set to 0 for hobby, or your commission/consulting rate if you design for clients.
Prep time
Minutes you spend setting up the printer (loading filament, clearing the bed, slicing). Multiplied by its own hourly rate.
Prep hourly rate
Your rate for prep work in $/hour — can differ from design or post-processing rates.
Post-processing
Minutes spent on the print after it finishes — sanding, painting, deburring, assembly. Multiplied by its own hourly rate.
Post-processing hourly rate
Your rate for finishing work in $/hour — can differ from design or prep rates.
Filament
Filament rows
Add one row per spool / color used in the print. The .gcode or .gcode.3mf import will pre-fill these with the color, type, and weight per filament.
Type
PLA, PLA Matte, PLA Silk, PLA+, PETG, ABS, ASA, or TPU. Metadata for your records — doesn’t affect cost directly.
Weight
Grams of that filament used. Auto-filled from import for Bambu Studio / OrcaSlicer.
Price ($/kg)
Your real spool price per kilogram. Cost = price ÷ 1000 × weight.
Printer
Preset
27 printer presets across Bambu Lab, Prusa, and Creality with real-world PLA-average wattage. Pick one to auto-fill wattage, price, and lifetime.
Wattage
Average power draw during printing — NOT peak. Example, Bambu P1S averages ~105W on PLA, not the 300W default other calculators use.
Electricity rate
Your utility rate per kWh — check your bill. US average is ~$0.16; California can be $0.30+.
Purchase price
What you paid for the printer. Used to amortize depreciation over its lifetime.
Lifetime hours
Realistic total print-hours before the printer needs major work. 5,000–10,000h is typical for consumer FDM.
AMS / MMU
Multi-material unit. Adds its own power draw and depreciation. Default 5.78W per Bambu AMS during active use.
Other Costs
Packaging
Per-unit cost of bags, tissue, hangtags, boxes.
Shipping
Per-unit shipping label / postage if you mail orders.
License
Monthly commercial-license fee (e.g. Patreon designer) divided across the units you sell per month.
Units / Month
How many units you print and sell per month. If you have a monthly license fee, this splits it into a per-unit cost. Also used in the Projects overview for portfolio revenue and profit totals.
Itemized costs — Flat
A name and a set $ per unit, used as-is. For things not worth measuring — adhesives, shop supplies.
Itemized costs — Pack
Pack cost ÷ pack size × qty used, counted in pieces. For countable hardware where quantity actually moves the price — magnets, inserts, LEDs.
Markup & Pricing
Markup %
0–99%. Suggested price = totalCost × (1 + markup/100). 30% markup on $2.71 cost = $3.52 sell price.
Margin at suggested
The profit margin (profit ÷ price) you’d actually get at the suggested price — shown next to Profit margin so you can compare it against My Price.
Spreadsheet Export
Summary tab
One row per project: unit cost, sell price, printed, sold, in stock, revenue, fees, and profit.
Activity log tab
Every print and sale entry, newest first. Price is per unit; Fees is the fee charged on that sale; Net = qty × price − fees − qty × unit cost. Import reads this tab to restore your data, so prints rows matter — they rebuild your stock counts.
Inventory tab
Current stock per project: in stock, unit cost, sell price, and value at sell price.
Value at sell price
In stock × sell price — what your shelf stock would bring in if every unit sold at the listed price. Costs aren’t subtracted, so it’s potential revenue, not profit.
Marketplace Fees tab
Your marketplace fee presets (Source, percent, flat $ per unit). On import they merge by name — the file’s values win.
Projects & Filaments tabs
Every calculator setting and filament row, so Import can rebuild a project completely on a new device. Included in both exports — the full-backup file is a complete backup on its own.
Cost items tab
One row per itemized cost — name, mode, and its Flat or Pack numbers. On import these rebuild each project’s itemized list and recompute its Other-costs total; if this tab is missing, the older single Other-per-unit number is used instead.
CSV export
Projects → Export → CSV saves one row per project — its settings plus filament grams, filament cost, and itemized-cost totals — for Google Sheets, Numbers, or any app that reads CSV. Importing it rebuilds each project with one combined filament row and one other-cost amount, so unit cost is preserved but the individual rows aren’t. Use .xlsx for backups.