How much does CNC machining cost?

Contents

• The short answer
• The CNC machining cost formula
• Worked example: why quantity matters so much
• CNC machining cost per hour: what sets the rate
• 12 cost drivers and the design change that cuts each
• Online CNC cost estimators: what they can and cannot do
• How to read a CNC quote
• How to compare suppliers fairly: landed cost

The short answer

There is no price per kilogram or per cubic centimetre for machined parts. Two parts of the same size and material can differ in price by ten times because one needs one setup and a few minutes of cutting, and the other needs four setups, a 5-axis machine and tight tolerances on twenty features. CNC machining cost is driven by time (programming, setup, cutting, finishing, inspection) much more than by material.

That is good news: most of the time on a quote is decided by design choices you can still change. The rest of this guide explains how.

The CNC machining cost formula

Almost every shop, whatever its software, builds a quote from the same parts:

Two components are fixed per order (programming and setup) and the rest are per part. That split explains nearly every pricing pattern engineers find surprising.

Worked example: why quantity matters so much

Take an aluminum 6061-T6 bracket, about 80 × 50 × 20 mm, with a pocket, four tapped holes and two reamed holes, black anodized. To keep the example independent of anyone's rates, count it in machine hours:

• Programming and setup: about 3 hours (two setups, one simple fixture).
• Cycle time: about 25 minutes per part across both setups.
• Anodizing: charged per batch with a minimum lot charge.

Going from 1 to 10 pieces cuts the machine hours per part by almost 80%. Going from 10 to 100 cuts them by another third, and at that point cycle time dominates, so further savings must come from design or from a dedicated fixture that shortens cycle time. The anodizing lot charge behaves the same way: painful on one part, negligible on a hundred.

Practical consequence: if you will need five prototypes over the next two months, order them together. If you are going to low-volume production, ask for prices at several quantity breaks so you can see where the curve flattens.

CNC machining cost per hour: what sets the rate

The hourly machine rate is the number people search for most, and it is the least useful in isolation. Rates differ greatly between regions (labour, rent, energy and overhead costs) and between machine types. A 5-axis machining centre costs far more per hour than a 3-axis mill or a simple lathe, because the machine, its tooling and the programmer behind it cost more.

But a higher rate can still produce a cheaper part. If a 5-axis machine finishes a part in one setup instead of four on a 3-axis mill, the saved setups, fixtures and re-clamping errors can outweigh the higher rate. Likewise a mill-turn centre that finishes a turned part with cross holes in one operation often beats a lathe plus a mill. Judge suppliers on the part price and landed cost, not the hourly rate.

What actually moves your price is the product of rate and time. Time is the half you control.

12 cost drivers and the design change that cuts each

Each item below names what drives CNC machining cost and one concrete change that reduces it. Every quote we send includes free DFM notes along these lines.

1. Internal corner radii. End mills are round, so sharp internal corners cannot be milled directly; they need small tools at slow speeds, or EDM. Change: make internal vertical radii at least one-third of the pocket depth and slightly larger than a standard tool radius (e.g. R3.2 for a Ø6 mm tool) so the tool does not dwell in the corner.
2. Pocket depth. Deep pockets need long, thin tools that must cut slowly to avoid deflection and chatter. Change: keep pocket depth under about 4× the tool diameter (tool diameter is set by the corner radius); if depth is only for weight saving, make the pocket shallower or open it from both sides.
3. Hole sizes and threads. Odd diameters need an interpolated toolpath or a special tool. Very deep tapped holes are slow and break taps. Change: use standard drill and reamer sizes, standard metric or UNC/UNF threads, and limit thread depth to about 1.5–2× the diameter; extra depth adds almost no strength.
4. Tolerances only where needed. Every tight callout means slower finishing, more measurement and more scrap risk. Change: use a general tolerance note (e.g. ISO 2768-mK) and tolerance individually only mating fits, datums and sealing faces. See our CNC machining tolerances chart.
5. Thin walls. Walls under about 1 mm in metal (1.5 mm in plastic) vibrate and deflect, forcing light cuts and careful fixturing. Change: thicken walls, add ribs, or shorten unsupported height.
6. Number of setups. Every time a part is flipped and re-clamped, the shop pays setup time and risks alignment error. Change: put features on as few faces as possible, avoid features on the underside that need a dedicated setup, and add a flat clamping surface. Where several faces are unavoidable, a single 5-axis setup may cost less overall.
7. Material choice. Machinability varies widely. Aluminum 6061 and brass C360 cut fast; stainless 316, titanium and PEEK cut slowly and wear tools. Change: choose the most machinable material that meets the requirement, e.g. 303 instead of 304 stainless where weldability is not needed, or 6061 instead of 7075 where strength allows. Compare grades on materials.
8. Stock size. A part sized 51 mm thick may need 60 mm plate and an extra facing operation, while 49 mm can come from 50 mm stock. Change: check standard bar and plate sizes and leave a few millimetres below them for facing. For turned parts, size outside diameters just under a standard bar diameter.
9. Finish choice. Each finish adds a process, handling and often a lot minimum; masking adds labor. Change: leave internal and hidden faces as machined (Ra 3.2 µm typical), specify cosmetic finishes only on visible faces, and choose Type II over hard anodize unless you need wear resistance. See surface finishes.
10. Quantity breaks. Setup and programming are spread over the batch. Change: batch prototypes into one order, and ask for quotes at two or three quantities (for example 5, 20, 50) to see where unit price levels off.
11. Lead time. Rush orders displace other work and may need overtime. Change: plan around a standard lead time when the schedule allows and use expedited service only for the parts on the critical path. Our standard is ≤7 days to make parts; expedited is 3–4 days.
12. Combining or splitting parts. A complex one-piece part can require a large block of stock and many setups; conversely, an assembly of five small parts multiplies setups and inspection. Change: evaluate both directions. Split a part when it removes deep pockets or 5-axis work; combine parts when it removes fasteners and repeated setups. Text engraving, cosmetic chamfers on every edge and decorative features are also worth questioning.

Online CNC cost estimators: what they can and cannot do

Instant-quote tools and online CNC machining cost estimators analyze your 3D model for volume, bounding box, features and material, and return a price in seconds. They are useful for early budget numbers and for comparing design variants: change a radius, re-upload, see the effect.

Their limits are equally clear. An algorithm reads geometry, not intent. It may not see that a tolerance on your PDF drawing needs a reaming operation, that a thread callout is non-standard, or that a thin wall will need special fixturing. Some platforms adjust the price after a manual review for exactly these reasons. A good workflow is to use an estimator for direction, then send the 3D file with a proper 2D drawing for a firm quote. How to prepare that package is covered in preparing CAD files for a CNC quote.

You can also do a rough CNC machining cost calculation yourself with the formula above: estimate setups and cycle time, multiply by a regional rate, add material and finishing, and divide setup by quantity. It will not be exact, but it shows which features matter.

How to read a CNC quote

A quote is only comparable if it states what it includes. Check for:

• Material grade and temper exactly as specified (6061-T6, not "aluminum"), and whether a material certificate is included.
• Tolerances accepted. Does the quote confirm your critical tolerances, or did the shop quote to its own default? Any exceptions should be written down.
• Finish details: anodize type and color, masking, thread treatment after finishing.
• Inspection: what is measured, whether you get a report, whether there is first-article approval before the batch.
• Lead time: manufacturing days versus delivery days. "7 days" can mean very different things.
• Shipping terms: EXW, FOB, DAP or DDP. This decides who pays freight, duty and import taxes.
• One-off charges: tooling, fixture or setup lines that will not repeat on a reorder.
• Remake or warranty terms if parts arrive out of tolerance.

Our quotes list unit price at your quantity, DFM notes on anything that drives cost or risk, and shipping cost to your country. Inspection reports with critical dimensions come with every order; see quality and inspection.

How to compare suppliers fairly: landed cost

The unit price on a quote is not what the part costs you. The number to compare is landed cost: what you pay per good part, delivered to your door, with duties and taxes settled.

• Shipping. Express courier (DHL, FedEx, UPS) is priced by actual or volumetric weight. For small machined parts it is often a modest share of the order; for large or heavy parts it can be significant.
• Import duties and taxes. Depending on your country and the part's tariff classification, imports can attract customs duty, VAT/GST and broker fees. Rates and rules change, so check the current situation for your country and product rather than relying on old figures.
• DDP versus DAP. Under DDP (Delivered Duty Paid) the seller pays duties and taxes, so the quoted figure is close to your landed cost and the courier does not stop the parcel for payment. Under DAP, you pay duties on arrival. DDP pricing is available from us on request.
• Quality cost. A cheaper part that fails inspection costs a re-order and weeks of schedule. Factor in inspection reports, first-article approval and remake terms.
• Engineering time. Communication speed, English-language DFM feedback and how many questions you have to answer all cost your time.

Domestic shops, overseas suppliers and online marketplaces each make sense in different situations. A local shop wins when you need parts tomorrow or need to stand next to the machine. Overseas machining is often attractive for prototypes and low-volume runs where a week of lead time is acceptable. Marketplaces route your order to a network of shops, which is convenient but can make it less clear who makes your part. We cover the trade-offs in CNC machining in China and marketplace vs direct supplier.