A CNC machining cost calculator that shows you why the number is what it is. Enter the part envelope, material, quantity and tolerance, and it estimates the per-part price from the physics of the job — how many cubic centimetres of metal come out as chips, how fast this material actually cuts, and how much one-time setup has to be spread across your batch. Every line is itemised, and the tool tells you which line is worth attacking. Rates are China-basis 2026 benchmarks; a typical US or European shop runs two to three times higher on machine time.
Estimate your part cost
How the calculation works
There is no black box here. The model runs on a short list of inputs and one physical relationship: cost of a machined feature is roughly proportional to the volume of material you have to remove, divided by how fast that material can be removed. Everything else is a multiplier on top.
- Stock volume = bounding box × 1.12, to allow for machining allowance and the fact that bar and plate come in standard sizes.
- Removed volume = stock volume − finished part volume. The finished volume is the bounding box times a fill factor set by part style: a solid plate fills about 85% of its box, a bracket about 45%, a thin-walled pocketed part about 32%.
- Cutting time = removed volume ÷ effective removal rate. The removal rate is the single most material-dependent number in the model: aluminium cuts roughly 45 cm³/min, 304 stainless 13, Ti-6Al-4V 7, Inconel 718 about 4. These are effective rates across roughing and finishing, not peak roughing rates.
- Cycle time = cutting time × 1.55, plus load and unload. The 1.55 covers tool changes, rapids, entry moves and the fact that a real programme is never cutting 100% of the time.
- Machine time cost = cycle time × the machine rate for that process, then multiplied by the tolerance factor. A tighter callout does not change the geometry — it changes how slowly the finishing pass runs and how many operations it takes.
- Tool wear = machine time cost × a per-material factor, from 8% for aluminium to 90% for Hastelloy. Hard materials do not just cut slower, they eat inserts.
- Setup and programming = programming hours + fixture hours × setups + first-article hours, multiplied by the machine rate, then divided by quantity. This is the only line that behaves completely differently at 5 pieces and 5,000 pieces.
- Surface finishing = the surface area of the bounding box, discounted to 85% because you never coat every face, multiplied by a per-dm² rate for the chosen finish, with a floor so that a small part still covers the minimum batch charge.
- Inspection and documentation = a per-part allowance that rises with how tight the tightest callout is, and falls with quantity: at 5,000 pieces the model assumes you sample rather than gauge every part, so this line is about half what it is at one piece.
The subtotal is then multiplied by 1.28 to cover overhead and margin. That last multiplier is the part buyers most often forget: a shop’s machine rate does not include rent, quality systems or profit.
Rates and inputs used (2026, China basis)
Machine rates reflect a Shenzhen supplier. Material prices are not hardcoded: the calculator reads a live feed from our own quoting system, which derives ten grades from Chinese futures closes and takes seven more from our own purchase records, refreshed three times a day on weekdays. The feed reports the snapshot time and the exchange rate it used, and every price it produces stays editable — your own purchase price is still a better input than anyone’s published average.
| Process | Rate (USD / hour) | Typical US / EU equivalent |
|---|---|---|
| 3-axis CNC milling | $45 | $40 – $120 |
| 4-axis CNC milling | $58 | $60 – $160 |
| 5-axis CNC milling | $90 | $150 – $300 |
| CNC turning (lathe) | $38 | $35 – $110 |
| Swiss-type turning | $85 | $70 – $280 |
Removal rates and tool-wear factors used by the calculator, per material family:
| Material family | Effective removal rate (cm³/min) | Tool wear added to machine time |
|---|---|---|
| Aluminium | 36 – 45 | 8 – 11% |
| Brass and copper | 30 – 50 | 7 – 12% |
| Carbon and alloy steel | 16 – 24 | 13 – 20% |
| Tool steel | 10 – 15 | 26 – 40% |
| Stainless steel | 10 – 18 | 20 – 35% |
| Titanium | 7 – 9 | 42 – 50% |
| Nickel alloys (Inconel, Monel, Hastelloy) | 4 – 7 | 55 – 90% |
| Engineering plastics | 48 – 58 | 5 – 7% |
| High-temperature plastics (PEEK, PPS, ULTEM) | 22 – 30 | 12 – 16% |
What moves the price most
Run two or three variations through the calculator and the same three levers show up every time, in this order.
1. Quantity, because of setup
Programming and fixturing are one-time costs. On a 5-piece order for a bracket-style part, setup is typically a third of the unit price; at 500 pieces it is under 2%. If your unit price looks high, check the setup line before you negotiate anything else — the fix may be batching rather than hard bargaining.
2. The bounding box, not the part weight
Cost tracks the volume of material removed, and removal is driven by how much space the part occupies. A 150 mm bracket that weighs 200 g can cost more to machine than a 60 mm block that weighs 900 g, because the bracket needs a bigger envelope of stock and a longer programme. Shrinking the envelope beats switching material surprisingly often.
3. Tolerance callouts, and how many of them there are
One ±0.01 mm callout on a mating bore is cheap and normal. The same callout repeated across every dimension on the drawing forces the machinist to treat the whole part as critical, and that is where the widely quoted 50–100% premium comes from — a figure that applies to the machining portion of the price, not to the whole quote. Apply tight tolerances to functional features and use ISO 2768-m general tolerances for the rest.
What does not move it much
Switching from 3-axis to 5-axis milling, on its own, is not the cost jump most people assume. 5-axis rates are roughly double 3-axis rates, but a 5-axis machine often eliminates two or three setups. For parts with features on four or more faces, the total frequently comes out lower. Run both through the calculator with the same geometry before assuming 3-axis is cheaper.
What this calculator does not include
It is deliberately scoped to the cost of a machined part, and honest about the edges:
- Wire and sinker EDM, grinding, honing and lapping are quoted separately. EDM removes very little volume but takes a long time, so a volume-based model would misprice it badly.
- Custom fixturing and soft jaws beyond the standard allowance. A part that needs a bespoke tombstone or a vacuum plate carries real cost the model only partly captures.
- Certification and documentation beyond a standard dimensional report. AS9102 first article, full PPAP, serialised lot records and third-party inspection are add-ons with their own price.
- Exotic stock forms and availability. A grade that has to be ordered as a one-off plate with a minimum mill quantity costs more than its price per kilo suggests.
- Freight, duties and tariffs. The model is ex-works. Landed cost depends on Incoterm, volume and destination.
- Tooling amortisation for very large runs where dedicated fixturing or a different process (casting, forging, moulding) becomes the better answer.
None of that makes the estimate useless — it makes it an estimate. Use it to sanity-check a quote, to decide whether a design change is worth pursuing, and to know which questions to ask. Then get a real number.
Frequently asked questions
How accurate is this CNC machining cost calculator?
For simple to moderately complex parts in common materials, the estimate typically lands within about 20 to 30% of a real quote, which is enough to compare design options or sanity-check a supplier. It is least accurate on very large parts, parts with unusual fixturing, and processes outside milling and turning. Treat it as an estimating tool, not a quotation.
Why is my per-part price so high at quantity 1?
Because programming, fixturing and first-article inspection are one-time costs and you are paying all of them for a single part. On a typical bracket, setup can be 70 to 85% of a one-off price. The machine time for that same part is often only $5 to $15. Increasing quantity is by far the fastest way to reduce the unit price.
Why does the calculator ask for a bounding box instead of the part weight?
Because machining cost is driven by the volume of material removed and how far the tool has to travel, not by how much the finished part weighs. Two parts of identical weight can differ by a factor of three in cost if one is compact and the other is a large thin frame. The bounding box captures the envelope that sets stock size and programme length.
Is 5-axis machining always more expensive than 3-axis?
No, and this is the most common misconception in cost estimation. A 5-axis machine has a higher hourly rate, but it can reach features that would otherwise need two or three separate setups on a 3-axis machine, each with its own fixture and re-datuming. For parts with features on four or more faces, 5-axis is frequently the cheaper total. Enter the same part with fewer setups and the higher rate and compare.
How much does a tight tolerance actually add?
Be careful how you read tolerance premiums, because most published figures are quoted against machine time only. The calculator applies a machine-time multiplier of 1.15 at ±0.05 mm, 1.30 at ±0.025 mm, 1.55 at ±0.01 mm and 1.95 at ±0.005 mm, measured against a ±0.05 mm general tolerance. Because machine time is only part of a quoted price, the effect on the total is smaller: on a typical bracket the premium works out at roughly 5–10% at ±0.05 mm and 15–30% at ±0.01 mm. On a part where machining dominates, such as an Inconel housing, the same callout can add 25% or more. Run your own part through the tool for the exact figure. The premium comes from slower finishing passes, extra operations such as grinding, and more inspection time — not from the machine being unable to hold the size.
Why are the machine rates lower than my local shop charges?
The defaults are China-basis 2026 rates. A US or European shop typically runs two to three times higher on machine time, and that gap is real. It narrows once you add freight, duty, and the management cost of an overseas supply chain, but for parts that fit in a box, the machine-time difference usually survives the landed-cost calculation. Set the rate field to your own supplier’s figure if you want to compare.
Does the calculator include the cost of the material I waste?
Partly. Stock volume is set at bounding box × 1.12, which covers the machining allowance, and material cost is then multiplied by 1.08 for offcut and remnant loss. What it does not model is a minimum mill order — if your grade only comes in a full plate, you pay for the plate, not for your part.
Where do the material prices come from?
From the same feed our quoting system uses. Ten grades — 6061, 7075 and 5083 aluminium; 303, 304 and 316L stainless; 45# and Q235 carbon steel; brass and copper — are derived from the Chinese futures close and converted at the prevailing CNY/USD rate. Seven more — H13 and S136 tool steel, TC4 and TA1 titanium, POM, PA6 and PEEK — come from our own purchase records, because there is no liquid futures contract for them. It refreshes three times a day on weekdays, and the calculator shows the snapshot time and the exchange rate it used. Grades with no feed at all fall back to an indicative default, and the note under the price field says so. A few grades are priced from a same-family grade rather than an exact match, and that note names which one.
Can I embed this calculator on my own site?
Yes, and it is free. The embed code is in the section below. The embedded copy reads the same live prices, so it stays current without any maintenance on your side, and it carries the same attribution line. There is no tracking script and no cookie.
Embed this calculator on your site
If you write about machining cost, sourcing or design for manufacture, you are welcome to put this calculator on your own page. It is free, there is no signup, no tracking script and no cookie. The embedded copy reads the same live material prices as this page and updates itself, so you never have to maintain it.
Rates in the embedded copy are China-basis 2026 and the material prices come from our own purchasing and the futures market. If you need different rates for your region, the machine rate and material price fields are both editable by the reader.
Related pages
- CNC Machining Cost Breakdown, Line by Line — the same cost structure explained without the calculator.
- 12 Ways to Cut CNC Part Cost — design changes that move the numbers above.
- Amortizing Tooling Cost Across Volumes — the setup line, in detail.
- MOQ Explained — why machine shops set minimums, and what they are really covering.
- Small Batch vs Mass Production — where the cost curve flattens.
- DFM Checklist Before You Order — catch the cost drivers before quoting.
- Tolerance Quick Reference — ISO 286 IT grades, ISO 2768 general tolerances and surface roughness by process.
- Metal Grade Cross Reference — AISI, EN, DIN, JIS and GB equivalents for 35 of those grades.
- CNC Machining vs 3D Printing — the breakeven, and where each process wins.
- Contact — send a drawing for a firm price.
Get a firm price for your part
Send a STEP file with the material, quantity and tolerance callouts. Quotes come back within one business day, and if a callout on the drawing is costing you more than it needs to, we will say so and price the alternative alongside it.
Request a quote or email [email protected].