Every FDM print has two real costs that most makers either estimate badly or ignore entirely: the filament consumed and the electricity burned during the print. Tracking only filament misses the runtime electricity bill; tracking only electricity misses your material investment. This calculator combines both into one honest number, with an optional markup to cover machine wear, failed prints and overhead. Whether you're a hobbyist who wants to know where their money goes, or a small seller trying to price prints without losing money, this tool gives you a transparent breakdown in seconds.
The formula, explained step by step
The calculation has two independent parts that add together, then an optional multiplier.
Part 1 — Filament cost:
Filament cost = (grams used ÷ spool weight in grams) × spool price
You're calculating what fraction of the spool you consumed, then multiplying by the spool's price. A standard 1 kg (1000 g) PLA spool at $22 costs exactly $0.022 per gram. A 24 g print uses 24 ÷ 1000 = 2.4% of the spool, costing 0.024 × $22 = $0.528. This fraction approach is more accurate than rounding to a "cost per gram" estimate because it reflects your exact spend.
Part 2 — Electricity cost:
Electricity cost = (printer watts ÷ 1000) × print time in hours × electricity rate ($/kWh)
You're converting watts to kilowatts (÷ 1000), then multiplying by time to get kilowatt-hours — the unit your electricity company bills. A 150 W printer running 3.5 hours consumes 150 ÷ 1000 × 3.5 = 0.525 kWh. At $0.15/kWh, that's $0.079. In Germany at €0.32/kWh, the same print costs €0.168 — more than double. Electricity rate matters enormously when printing at scale.
Markup (optional):
Total = (filament cost + electricity cost) × (1 + markup ÷ 100)
A 20% markup on a $0.61 base cost adds $0.12, bringing the total to $0.73. This covers machine depreciation (a $300 printer spread over 500 hours of printing costs $0.60/h), filament waste from purge lines and failed first layers, and nozzle wear.
How to use this calculator
- Open your slicer and slice your model. PrusaSlicer, Cura, OrcaSlicer and Bambu Studio all show a print summary after slicing. Look for "Filament used" in grams and the estimated print time in hours and minutes.
- Enter the filament weight and print time. Convert the print time to decimal hours (e.g., 3h 30m = 3.5 h). The filament weight from the slicer is already in grams.
- Enter your spool price and weight. The spool weight is the net filament weight — usually 1000 g for a 1 kg spool. The spool itself weighs 200–250 g extra and is not counted. Check the filament packaging for the net weight.
- Enter your printer's wattage. If you don't know it, use 150 W for a standard Ender 3 or Prusa MK4 class printer, 200–250 W for a Bambu Lab X1C or P1S, and 300+ W for large-format printers. A smart plug with power monitoring (like a Kasa EP25 or Shelly Plug) gives you the real number.
- Enter your electricity rate. Find this on your utility bill or search "[your country] average electricity rate kWh". US average is around $0.13–$0.17/kWh. UK is about £0.24/kWh. Germany averages around €0.32/kWh.
- Add a markup if needed. For personal use, leave this at 0. For selling, a 15–25% markup covers machine wear without over-pricing your prints.
Real-world examples
Example 1: Small decorative PLA print (Ender 3, standard conditions)
A 24 g decorative miniature base, printed on an Ender 3 Neo at 150 W, 3.5 h print time, $22/kg PLA spool, US electricity at $0.14/kWh, no markup:
Filament: 24 ÷ 1000 × $22 = $0.53
Electricity: 0.15 kW × 3.5 h × $0.14 = $0.074
Total: $0.60 — roughly the cost of a cheap candy bar to produce a physical object.
Example 2: Functional PETG bracket (Bambu Lab P1S)
A 95 g engineering bracket in PETG, printed on a Bambu P1S at 220 W, 5.5 h, $28/kg PETG spool, $0.15/kWh, 20% markup for commercial use:
Filament: 95 ÷ 1000 × $28 = $2.66
Electricity: 0.22 kW × 5.5 h × $0.15 = $0.18
Subtotal: $2.84 × 1.20 markup = $3.41
This is your true cost before any labor or profit margin.
Example 3: Large ABS part with overnight print (Europe)
A 340 g ABS enclosure printed in an enclosure-equipped printer at 280 W, 16 h overnight, $26/kg spool, €0.30/kWh (Germany):
Filament: 340 ÷ 1000 × $26 = $8.84
Electricity: 0.28 kW × 16 h × $0.30 = €1.34
Total ≈ $10.18 + €1.34 — electricity becomes a significant fraction (12%) of total cost at European rates. This is why high-speed printing that cuts a 16 h job to 8 h saves real money in high-electricity-cost countries.
Example 4: Print farm economics
A print farm running 6 printers simultaneously, each printing a 50 g part in 4 h at 150 W, $20/kg PLA, $0.13/kWh:
Per printer: (50 ÷ 1000 × $20) + (0.15 × 4 × $0.13) = $1.00 + $0.078 = $1.078
× 6 printers = $6.47 total material+electricity cost per batch. Tracked over a month of 3 batches/day, this insight tells the farm operator where their biggest costs lie and whether bulk filament purchasing makes sense.
Who uses this calculator
Hobbyists and makers use it to understand where their money goes. It's surprisingly common to discover that a print you assumed cost $3 actually cost $0.80 — or vice versa when using expensive materials at high electricity rates.
Etsy and eBay sellers use it as the starting point for pricing. The output of this calculator feeds directly into the 3D Print Price Calculator to add labor, margin and marketplace fees.
Print farm operators use it to track cost per part and evaluate whether upgrading to faster printers (higher wattage) offsets the reduced cycle time.
3D printing enthusiasts buying new filament compare materials by their true cost per print, not just the sticker price per spool — a $35 engineering-grade PETG may cost less per print than a $20 budget PLA that produces more failures.
Common mistakes to avoid
Using nameplate wattage instead of actual draw. A printer rated at 350 W on its label may only draw 120–180 W during steady-state printing (after the bed reaches temperature). The nameplate is the peak draw; real average draw is 40–60% lower for most desktop printers. Use a power meter for accurate data.
Forgetting that spool weight is net filament only. A "1 kg spool" weighs 1200–1300 g total. The spool itself weighs 200–250 g. Enter 1000 (not 1250) in the spool weight field, or weigh the empty spool and subtract.
Not accounting for failure rate. If 1 in 10 prints fails mid-way, your effective filament cost is 10% higher. Either add a 10% markup or mentally adjust your expectations. Failure rates are higher with new filament brands, new materials or complex overhangs.
Using slicer time without adding heating time. Most slicers report only the active print time. Add 5–10 minutes for bed and hotend warmup, especially relevant for shorter prints where warmup is a large fraction of total runtime.
Practical tips for reducing print costs
Measure your actual power draw. A $15–25 smart plug with energy monitoring (Kasa EP25, Shelly Plug S, TP-Link Tapo P115) plugs between your printer and the wall socket and logs actual kWh consumed. After a few prints, you'll have your real average wattage — often 20–30% lower than you assumed.
Buy filament in multi-pack bundles. The cost per kg drops significantly when buying 3–5 spools at once. A $22/kg single spool often drops to $17–19/kg in a 5-pack. On a print farm running 200 kg/year, that's $600–1000 in annual savings.
Track actual vs. estimated weight. Weigh your finished prints on a kitchen scale. Consistently higher-than-expected weights suggest your slicer's density setting is off, or you're over-extruding. Consistently lower weights can indicate under-extrusion.
Print at night in high-rate time-of-use plans. If your electricity provider uses time-of-use pricing, off-peak rates (typically 9pm–7am) can be 30–50% cheaper than peak rates. A 16-hour print started at 9pm runs almost entirely at off-peak rates.
Use the markup field strategically. Instead of guessing, calculate your printer's depreciation cost: printer price ÷ expected lifetime hours. A $400 printer lasting 2000 print hours costs $0.20/h in depreciation. Add this to your markup calculation for accurate cost tracking.