How Much Does CNC Machining Cost? What Drives a Quote
CNC machining cost depends on material, tolerance, geometry, quantity and finish. Learn what drives a quote — and how to get an accurate one in 24 hours.
How Much Does CNC Machining Cost? What Drives Your Quote
If you have sent the same drawing to three CNC machining suppliers, you have probably received three very different prices — and wondered which one to trust. That is normal. A CNC quote is not a catalogue price. It is a calculation built from your drawing, and every line on that drawing moves the number.
This guide explains what actually drives the cost of a custom CNC machined part, so you can read a quote line by line, avoid paying for precision you do not need, and send an RFQ that gets you a comparable, accurate price. At Golden Rainbow, we quote the same way: standard tolerance ±0.05 mm, key features up to ±0.01 mm subject to drawing review, from 1 piece, with prototypes in 3–7 working days and production in 10–15 working days.
2. Tolerance: The Biggest Cost Lever You Control
Tolerance is usually the single largest cost lever, and the one buyers over-specify most often.
A standard tolerance of ±0.05 mm can be held on most features with normal machining, normal inspection and normal speed. Tightening a feature to ±0.01 mm is a different job: slower feeds, more careful fixturing, temperature-stable measurement, and often a separate finishing pass. The cost does not rise in proportion — it can jump several times over for a single feature.
So apply tight tolerances only where they matter:
- Tight (±0.01 mm): bearing bores, sealing faces, mating interfaces, and features that control assembly fit. These are the features we review drawing by drawing before confirming ±0.01 mm.
- Standard (±0.05 mm): most general dimensions, non-critical holes, overall sizes.
- Loose (±0.1 mm or open): cosmetic edges, clearance features, anything that does not touch another part.
Do not put ±0.01 mm on every dimension "to be safe". A drawing with tight tolerances everywhere reads as a part that will be slow, expensive and risky to make — and suppliers will price it that way. If you are unsure which features are critical, mark them, and let the supplier confirm the rest.
4. Quantity: Why 1 Piece and 500 Pieces Are Different Products
Setup and programming are fixed costs. On a 1-piece prototype, you pay all of them. On 500 pieces, the same setup cost is spread across 500 parts, so the unit price falls sharply — even though material and machining time per part barely change.
That is also why the cheapest unit price is not always the cheapest order. A supplier who charges a separate setup fee and a low unit price may be cheaper at 500 pieces and more expensive at 10. Ask for the quote broken down — setup, unit price, material, finishing — and compare at your actual quantity, not at the quantity in someone else's example.
Golden Rainbow takes orders from 1 piece, so prototypes and small batches are quoted the same way as production: the setup is real, it is shown in the price, and it falls per unit as quantity rises.
