When you first get into 3D printing, it's easy to think the primary cost is the filament. You buy a spool for $25, print a few things, and when it runs out, you buy another. But the true cost of a 3D print is a bit more complex. To accurately budget for your hobby or price your prints for a business, you need to consider several factors.

1. Filament Cost

This is the most obvious cost. However, simply dividing the spool cost by the number of prints is inaccurate. The correct way is to determine cost based on weight. Your slicer software (like Cura, PrusaSlicer, or Bambu Studio) is your best friend here. After slicing a model, it will tell you exactly how much filament, in grams, the print will consume.

The formula is straightforward:

Material Cost = (Print Weight / Spool Weight) * Spool Cost

This is the calculation at the core of our 3D Cal tool.

2. Electricity Cost

This is the most commonly overlooked expense. A 3D printer, with its heated bed, hotend, motors, and fans, consumes a significant amount of electricity, especially during long prints. A typical hobbyist printer can range from 150W to 350W on average.

To calculate this, you need to know:

• Your printer's average power consumption in Watts (W).
• The total print duration in hours.
• Your local electricity rate, usually priced per kilowatt-hour (kWh).

The formula is:

Electricity Cost = (Printer Wattage / 1000) * Print Duration (hours) * Cost per kWh

A 10-hour print on a 250W printer with electricity at $0.15/kWh would cost (250/1000) * 10 * 0.15 = $0.375. It may not seem like much for one print, but it adds up quickly over hundreds of hours.

3. Wear and Tear / Maintenance

While harder to quantify on a per-print basis, this is a real cost. Parts like nozzles, stepper motors, belts, and fans have a finite lifespan. A good practice is to set aside a small percentage (e.g., 5-10%) of the combined material and electricity cost of each print for a "maintenance fund." This ensures you're covered when a part inevitably fails.

4. Your Time (for Businesses)

If you are running a printing business, your time is a valuable asset. This includes the time spent slicing the model, preparing the printer, post-processing the print (removing supports, sanding), and packing/shipping. You should factor in an hourly rate for your labor when pricing products for sale.

Conclusion

By understanding and calculating these factors, you can get a much more accurate picture of your 3D printing expenses. Tools like 3D Cal help automate this process, allowing you to focus more on creating and less on accounting.