- Cost per part = (materials + packaging + labour + machine time + other batch costs) / parts made
- Price = cost per part / (1 - margin)
Margin is the share of the price you keep. A 50% margin means the price is twice the cost. A 60% margin means 2.5 times.
A worked example: 6061 aluminium mounting bracket
A small CNC shop often runs repeat parts in jobs of 10 to 100. This example machines 10 brackets from 1/2 x 2 in 6061 flat bar, 3.125 in of bar each, 20 minutes on the mill per part and one 30 minute setup.
Step by step
- List what goes into one batch. Write down every material, with the amount you use for one batch of 10 parts, and the packaging for each part.
- Price each material from the pack you bought. Divide the pack price by the pack size, then multiply by the amount you used. Change units first so grams go with grams. In the example the materials and packaging come to $40.52.
- Add your time. Count every minute: making, cleaning up, packing. 50 min at $30.00 an hour is $25.00.
- Add time on the machine. Machines cost money to buy, run and repair. 3 h 20 min at $50.00 an hour is $166.67.
- Add the other costs of the batch. Setup, 30 minutes once per job: $25.00.
- Divide by the parts you made. $257.18 / 10 = $25.72 per part. Use what you really got, not what the recipe promised.
- Set the price from the margin you want. Price = cost / (1 - margin). At a 30% margin: $25.72 / 0.70 = $36.74.
Check the wholesale price
Shops that buy wholesale usually pay about half of the shop price. Half of $36.74 is $18.37. That is below the $25.72 cost, so this price only works for direct sales. Raise the price or lower the cost before you sell wholesale.
What CNC machine shops often leave out
- Setup time. Fixturing, tool changes and the first-article check happen once per job. Spread them over the parts, and charge more per part on small jobs.
- Tool wear. End mills, inserts and drills wear out. A few cents to a dollar a part adds up over a year.
- Bar you cannot use. Kerf, facing and the short end of the bar are part of the cost of the part.
- Deburring and inspection. Minutes away from the machine still cost you.
- Material price changes. Aluminium and steel prices move. Check your stock price before you quote a big job.
Try it with your own numbers
The cnc machining cost calculator starts with this example. Change the prices and amounts to yours and you have your cost and price in a minute. Save it as a recipe in Stockria and the cost stays right when a supplier changes a price.
Frequently asked questions
How do I price a CNC machining job?
Add material, machine minutes at your machine rate, labour minutes at your labour rate, tooling and the setup spread over the parts. That is the cost per part. Divide by 1 minus your margin for the price.
What hourly rate should a small CNC shop charge?
Work out your own: the machine's cost spread over its working hours, plus power, tooling, rent and your pay. Many small US shops land between $35 and $60 an hour for 3-axis milling, but your number must come from your costs.
How does quantity change the price per part?
Setup is paid once, so it shrinks per part as the job grows. A 30 minute setup at $50 an hour adds $2.50 a part on a job of 10, and only 25 cents on a job of 100.
Should I charge for material by weight or by length?
Charge for what you buy and what you use. If you buy bar by the foot, price the inches each part uses, kerf and facing included. If you buy by weight, price the weight of the blank, not the finished part.
