A drawing goes out to three shops and the quotes come back a factor of two apart. The machine tool is rarely the reason. The gap is in the basis nobody wrote down: whether programming and setup sit inside the figure, how much material loss is carried, whether the finish is priced by the kilogram or by the piece.
This page takes a CNC machining quote apart into the five lines it is actually made of, gives the arithmetic and the default basis behind each one, and shows how to assemble a comparable price range in five minutes with our online calculator.
The answer up front: CNC machining cost = material cost + programming and setup + machining + post-processing + overhead, margin and tax. The first four lines are cost; the fifth sits on the quotation layer. One-off charges have to be spread across the batch before any of it becomes a unit price.
CNC Machining Cost per Hour
The hourly rate is the number most buyers ask for first, so it comes before anything else. The table below is the calculator’s default tiering — a reference basis, not a market price. Change it to your own shop’s equipment depreciation and labour (the slider runs from ¥30/h to ¥300/h).
| Machine route | Default rate | Typical work |
|---|---|---|
| CNC lathe | ¥50/h | Outside diameter, face, threads |
| Drill-tap machining centre | ¥50/h | Drilling and tapping in batches |
| Three-axis machining centre | ¥80/h | Plates, pockets, hole patterns |
| Four-axis machining centre | ¥120/h | Multi-face parts, fewer setups |
| Five-axis machining centre | ¥200/h | Complex surfaces, impellers, mould work |
Tick more than one route and the highest rate wins, because the dominant machine sets the pace. The rate is only one of the five lines below, which is the point worth holding on to: a quote built on the right rate and the wrong basis is still the wrong quote.
Material Cost: Priced on the Blank
Material is costed on the blank weight, never the finished part weight. Add an allowance per side to the part outline: bar and plate stock take 2–3 mm, forgings and castings 4–5 mm (the calculator defaults are 3 / 2.5 / 4 / 4 mm).
Unit prices follow the calculator’s default basis (a reference basis, and editable): 45# steel ¥5.5/kg, Q235 ¥4.5/kg, 40Cr ¥6/kg, POM ¥12/kg, 304 stainless steel ¥17/kg, aluminium 6061 ¥23/kg, brass H62 ¥45/kg, copper T2 ¥50/kg. Unit prices move faster than machine rates, so before a long-run order is signed, overwrite them with the week’s purchasing price.
The purchasing loss factor defaults to 1.15 — stock is bought with a 15% cushion — and can be set anywhere from 1.00 to 1.50. Bar ends, the clamping stub and saw-kerf loss all live in this number. Where full bars are bought and the job nests well, 1.05–1.10 is closer to what actually happens.
Worked example, a 45# disc ⌀70 × 25 mm: the blank is taken as ⌀76 × 31 mm, volume π/4 × 7.6² × 3.1 ≈ 140.6 cm³, and multiplying by a density of 7.85 g/cm³ gives 1.104 kg. Material cost = 1.104 × 5.5 × 1.15 ≈ ¥6.98 per piece.
Programming and Setup: A One-Off You Have to Spread
Programming, first-article proving, tool setting and fixture preparation happen once, at the head of the order. The calculator defaults to 2 h of setup programming (adjustable between 0.5 and 8 h) and a fixture cost of ¥0, which you replace with a real amount when a dedicated fixture has to be made. On a repeat order, where the programme is reused, both go to zero.
Example: 2 × 50 = ¥100 for the whole order, which spreads to ¥2.00 per piece across 50 pieces. Run the same drawing as 5 pieces and that one line becomes ¥20.00 per piece. A tenfold batch difference lands almost entirely here — this is the main reason a small batch looks expensive per piece.
Machining: Time Multiplied by Rate
Cutting time is added up feature by feature: turning the outside diameter, facing, drilling, tapping, boring, pockets. The calculator supplies conservative template values that can be overridden row by row; where trial-cut data exists, replace the template with the measured time.
Difficulty factors are anchored at 45# = 1.0: aluminium 0.8, POM 0.7, copper and Q235 0.9, 40Cr 1.2, stainless steel 1.4, titanium 2.0. The precision factor multiplies cutting time only: IT11–12 takes 1.0, IT8–9 takes 1.2, IT6–7 takes 1.5. Unspecified tolerances on a drawing are graded per GB/T 1804-2000 Table 1 into fine (f), medium (m), coarse © and very coarse (v), equivalent to ISO 2768-1:1989; the IT1–IT18 dimension-tolerance grades come from GB/T 1800.1-2020, and the precision factor hangs on that step.
Example: cutting time 12 min per piece, rate ¥50/h, difficulty 1.0, IT8–9 factor 1.2 → 0.2 × 50 × 1.2 = ¥12.00. Clamping overridden to 8 min → 8 ÷ 60 × 50 = ¥6.67. Machining comes to ¥18.67 per piece. Check pilot-hole sizes before anything is drilled and tapped — use the pilot hole calculator or the tap drill size chart. One mis-drilled hole costs several tens of minutes of machine time in rework.
Post-Processing: The Basis That Goes Wrong Most Often
Black oxide, zinc plating, nickel plating, anodising, sandblasting and spray coating are priced on three different bases: per kg of blank weight, per piece, or per area (dm²). The default unit price is ¥1–4/kg, with a separate minimum charge of ¥50.
Example: black oxide priced per kg, 1.104 × 1 = ¥1.10, which falls below the minimum, so the line is charged at ¥50 for the piece. This is both the dearest and the most easily mis-set line in the example — the minimum charge is a floor set per piece, and small parts run into it every time. On batch work, have the finisher quote per batch, or override this line with a batch-level basis.
Overhead, Margin and Tax
Order-level costs default to ¥400 (freight, inspection and the order-tracking share); where the total order cost falls below the subcontract minimum start-up charge of ¥150, quote at ¥150. Margin is the unit cost multiplied by a factor: 1.25 on the trade-peer basis, 1.7 for end customers, adjustable between 1.05 and 2.5. The range displayed around it is ±30% by default, and it is a display width, not a confidence interval. VAT defaults to 13% and acts on the quotation layer only; the cost layer is always pre-tax.
The example closes out like this: unit variable cost = 6.98 + 12.00 + 6.67 + 50.00 = ¥75.65; order total cost = 50 × 75.65 + 100 + 400 = ¥4,282.50; unit cost ¥85.65. Trade-peer quote ¥107.06, end-customer quote ¥145.61, and ¥164.54 for the end-customer quote with 13% VAT included.
Running the Numbers in Five Minutes
Open the CNC quote calculator and walk the six steps: drawing upload (optional — the AI reads dimensions and features off the image, and every row it returns can be corrected) → part data (dimensions, blank form, material, batch) → machining features (enter feature and time row by row, and the result recalculates as you type) → process and post-processing (machine route, number of clampings, post-processing basis) → price assumptions (rate, difficulty, loss, margin, tax) → estimate result. The six steps are set out one by one in the calculator manual.
What comes back is not a single number but a range with two floors: trade peer and end customer, pre-tax and tax-inclusive, with the arithmetic shown line by line. Note the two ends of the range and move on; a point price is not what this stage is for.
Below the result sits the calibration area: save the costing together with every parameter override, enter the price you actually won once the customer comes back, and the page returns the deviation rate on the spot. That deviation rate is what you feed back into the rates — after a few jobs, the defaults in the table should be your own shop’s basis.
Frequently Asked Questions
How is a CNC machining price worked out?
Five lines added together: material cost + programming and setup + machining + post-processing + overhead, margin and tax. The first four are cost; spread the one-off charges across the batch to reach a unit cost, then multiply by the margin factor to reach a quote. Get the basis of any one line wrong and the other four can be perfectly calculated without saving the answer. To test those five lines on your own drawing, open the CNC quote calculator and change one input at a time.
How much does CNC machining cost per hour?
The default tiering is ¥50/h (CNC lathe, drill-tap), ¥80/h (three-axis), ¥120/h (four-axis) and ¥200/h (five-axis), all on a reference basis. The real rate is set by the equipment, the shift pattern and local labour. Most of the gap between a five-axis and a three-axis rate sits in depreciation and programming time, not in the cutting itself.
How do you cost a machining job?
Fix the basis before doing any arithmetic: batch size, blank allowance, loss factor, number of clampings and the post-processing pricing basis. Change any one of those five and the answer changes. Costing gives a range, not a point; a job below the minimum start-up charge is quoted at that minimum.
How does batch size change the price?
Only programming and setup, and the order-level costs, have to be spread. Material, machining and post-processing all run per piece. Double the batch and only the spread lines come down — nothing else moves, which is the arithmetic behind small batches costing more.
Before You Send the Quote
A self-check list ahead of quoting:
- Is the batch size written down, and are the one-off charges spread against it?
- Is the blank allowance 3 mm for bar and 2.5 mm for plate, or the actual blank size?
- Is the loss factor the 1.15 default, or corrected to the real utilisation?
- Is the clamping count based on dialling in, or on soft jaws and a fixture?
- Is post-processing quoted per batch by the finisher, or squeezed against the ¥50 minimum?
- Does the quotation state a tax-inclusive or a tax-exclusive figure?
Three sentences to carry away. First, price differences are mostly basis differences — write batch size, loss, clamping and post-processing into the header of every quotation. Second, one-off charges must be spread across the batch; never compare a five-piece job against a production price. Third, when a job falls below the minimum start-up charge or the post-processing minimum, quote the floor price rather than forcing the unit cost through.
Once the basis is fixed, the same part becomes comparable. Have the drawing and the six parameters above ready and let the calculator return a first range; to have the rates, process route and post-processing setup of your own shop checked line by line, send the drawing and the parameters to our quoting page and our engineers will verify them and show the arithmetic for each line.
References
- GB/T 1800.1-2020 Product geometry specification (GPS) — Linear dimension tolerances ISO code system — Part 1: Basis of tolerances, deviations and fits
- GB/T 1804-2000 General tolerances — Tolerances for linear and angular dimensions without individual tolerance indications (eqv ISO 2768-1:1989; tolerance grades: fine f, medium m, coarse c, very coarse v)
- ISO 2768-1:1989 General tolerances — Part 1: Tolerances for linear and angular dimensions without individual tolerance indications
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