3DQ uses a series of calculations to determine the cost of 3D printing jobs. This reference guide explains all the formulas used in the application.

The cost of filament used in a print is calculated based on the weight used and the price per kilogram:

filament_cost = (grams_used / 1000) * price_per_kg

Where:

• grams_used is the amount of filament used in grams
• price_per_kg is the price of the filament per kilogram

For example, if you use 100g of filament that costs £25/kg:

filament_cost = (100 / 1000) * 25 = £2.50

Printer depreciation accounts for the gradual wear and tear on your printer over time:

depreciation_per_hour = (price + service_cost) / depreciation_time
depreciation_cost = print_time * depreciation_per_hour

Where:

• price is the purchase price of the printer
• service_cost is the estimated maintenance costs over the printer's lifetime. 10% of the cost of the printer itself can be used as a rough average for service cost.
• depreciation_time is the expected lifetime of the printer in hours
• print_time is the duration of the print in hours

For example, if your printer cost £1099, with service costs at 10% of that (£109.90), and a 5000-hour lifetime, and your print takes 5 hours:

depreciation_per_hour = (1099 + 109.90) / 5000 = £0.24/hour
depreciation_cost = 5 * 0.24 = £1.20

Power cost accounts for the electricity used during printing:

power_cost = print_time * power_usage * electricity_cost_per_kwh / 1000

Where:

• print_time is the duration of the print in hours
• power_usage is the printer's power consumption in watts
• electricity_cost_per_kwh is the cost of electricity per kilowatt-hour
• Division by 1000 converts watts to kilowatts

For example, if your printer uses 100W, electricity costs £0.2166/kWh, and your print takes 5 hours:

power_cost = 5 * 100 * 0.2166 / 1000 = £0.1083

Labour cost accounts for the time spent on design, preparation, post-processing, and other tasks:

total_minutes = design_minutes + preparation_minutes + post_processing_minutes + other_minutes
labour_cost = (total_minutes / 60) * labour_rate_per_hour

Where:

• design_minutes, preparation_minutes, post_processing_minutes, and other_minutes are the time spent on each task
• labour_rate_per_hour is the hourly rate for labor

For example, if you spend 30 minutes on design, 10 minutes on preparation, 15 minutes on post-processing, and your labor rate is £13/hour:

total_minutes = 30 + 10 + 15 + 0 = 55 minutes
labour_cost = (55 / 60) * 13 = £10.17

Hardware cost is simply the unit price multiplied by the quantity:

hardware_cost = unit_price * quantity

The total cost of a print job is calculated as follows:

# Per-unit costs
per_unit_subtotal = filament_cost + hardware_cost + power_cost + depreciation_cost + labour_cost

# Apply quantity
subtotal = per_unit_subtotal * quantity

# Apply markup, discount, and tax
markup = subtotal * (markup_percent / 100)
total_before_discount = subtotal + markup
discount = total_before_discount * (discount_percent / 100)
total_after_discount = total_before_discount - discount
tax = total_after_discount * (tax_rate / 100)  # If tax rate > 0
final_total = total_after_discount + tax

Where:

• markup_percent is the percentage markup applied to the subtotal
• discount_percent is the percentage discount applied to the total after markup
• tax_rate is the percentage tax rate applied to the total after discount (if configured)

For example, with a per-unit subtotal of £20, quantity of 3, 75% markup, 10% discount, and 20% tax:

per_unit_subtotal = £20
subtotal = £20 * 3 = £60
markup = £60 * (75 / 100) = £45
total_before_discount = £60 + £45 = £105
discount = £105 * (10 / 100) = £10.50
total_after_discount = £105 - £10.50 = £94.50
tax = £94.50 * (20 / 100) = £18.90
final_total = £94.50 + £18.90 = £113.40