How to Cost Filament, Electricity and Time per Print

Sell a print for R200 when it actually cost you R260 to make, and you are losing money on every order without realising it. Costing a 3D print properly means adding three things most makers forget to total: the filament you burned, the electricity the printer drew, and a slice of the machine's own wear. Get all three on the page and your pricing finally reflects reality instead of guesswork.

Quick Answer

Cost per print equals filament grams times your cost-per-gram, plus printer wattage times print hours times your Eskom or municipal kWh tariff, plus an hourly machine depreciation allocation. Miss any one of those and you quietly undercharge. A typical mid-size print might land near R45 to R70 in true cost once all three are counted.

Step 1: Cost the Filament

Start with the easy part. Take the spool price and divide by its weight in grams to get a cost per gram.

1. Note the spool price, say R350 for a 1 kg roll.
2. Divide by 1000 grams: R350 / 1000 = R0.35 per gram.
3. Read the filament weight for your print from your slicer's estimate, for example 60 g.
4. Multiply: 60 g times R0.35 = R21.00 in material.

Your slicer reports grams used for every sliced model, so this number is reliable. Use the actual spool price you paid, not the shelf price of a different brand, or your maths drifts.

Step 2: Cost the Electricity

This is the component people skip, and it adds up over long prints. You need three figures: the printer's power draw, the print time, and your local tariff.

1. Find the printer's average running wattage. A desktop FDM machine typically draws far less than its rated maximum once the bed is up to temperature, often in the region of 70 to 150 watts during a print.
2. Convert to kilowatts: 120 W / 1000 = 0.12 kW.
3. Multiply by print hours: 0.12 kW times 8 hours = 0.96 kWh.
4. Multiply by your tariff. Check your latest municipal or Eskom bill for the rand-per-kWh rate, since it varies by area and tariff block. At an example R2.80 per kWh: 0.96 kWh times R2.80 = R2.69.

The number looks small per print, but on a workshop running prints daily it becomes a real monthly line item. Always pull your own tariff off a recent bill rather than assuming a national average.

Measuring Wattage Accurately

Rated wattage on the label is the peak, not the average. For a precise figure, a plug-in energy meter logs the real draw across a full print, including the heat-up spike and the steady-state running load. If you would rather estimate, use a conservative average for your machine type and accept a small margin.

Step 3: Allocate Machine Depreciation

Your printer wears out, and that cost belongs in every print. Treat the machine like any tool with a working life.

1. Take the printer's purchase price, for example R8,000.
2. Estimate its useful printing life in hours. A conservative figure for a hobby-grade machine might be 3,000 hours before major parts need replacing.
3. Divide: R8,000 / 3,000 hours = R2.67 per hour.
4. Multiply by print time: R2.67 times 8 hours = R21.36.

This allocation also quietly covers consumables that wear with use, nozzles, belts, the print surface, so you are not blindsided by replacement costs later. If you want a realistic working life and replacement-part picture, the 3D printer range at Evetech is a useful reference for what current machines and spares actually cost.

Step 4: Add It Up

For the worked example above:

• Filament: R21.00
• Electricity: R2.69
• Depreciation: R21.36
• True cost: R45.05

Notice that depreciation rivalled the filament cost. That is the figure most casual pricing ignores entirely, which is exactly why hobby sellers tend to undercharge.

Step 5: Add Labour and Margin

True cost is your floor, not your price. On top of it, account for your time, slicing, supervision, support removal, post-processing, at an hourly rate you are happy with, then add a margin for profit and failed prints. A sensible buffer for failures matters because not every print succeeds, and a scrapped job still consumed filament and power.

Keeping a few spares and finishing tools on hand reduces downtime between jobs, and the accessories worth keeping next to the printer cover the small extras that keep a print queue moving.

A Quick Costing Habit

Build a simple spreadsheet with cells for grams, cost-per-gram, wattage, hours, tariff and depreciation-per-hour. Plug in each print's numbers and the total calculates itself. Once it is set up, costing a job takes under a minute and you never price blind again.

Frequently Asked Questions

What is the most commonly forgotten cost in 3D printing?

Machine depreciation. Makers price filament and sometimes electricity, but rarely allocate the printer's wear per hour. On longer prints this allocation can rival the material cost, so leaving it out understates the true cost significantly.

How do I find my electricity tariff for print costing?

Read the rand-per-kWh rate off your most recent municipal or Eskom bill. Tariffs vary by area and consumption block, so use your own figure rather than a national average for accurate costing.

How do I measure my printer's real power draw?

A plug-in energy meter logs the actual kWh used across a full print, including heat-up and steady running. Without one, use a conservative average wattage for your machine type and accept a small margin of error.

Should I include failed prints in my pricing?

Yes. Not every print succeeds, and a failed job still consumes filament and power. Add a small margin to cover scrapped prints so your pricing stays profitable across a batch rather than just on perfect runs.

How long does a hobby 3D printer last for depreciation purposes?

A conservative estimate is a few thousand printing hours before major parts need replacing. Use a realistic working-life figure for your machine, then divide the purchase price by those hours to get a cost per hour.