Every CNC quote has to answer two questions: what does this part cost us, and what price do we give the customer? This CNC machining cost calculator answers both. Enter the order quantity, material, machine time and your machine hourly rate; the tool works out the unit cost per part, adds a risk allowance and profit as separate lines, rounds the quote to a commercial figure and shows the order total. All amounts are in whatever currency you use.
The calculator has two modes. Estimate from the drawing is for the common case where you have no sample yet and estimate the cycle time from the technical drawing; the result is an estimated quote. From sample / pilot batch data is for when you have clamped the part, machined it and measured the real time and insert consumption; the result is a verified quote. The result screen reminds you which mode you used, because the two prices are not equally reliable.
1. Order and material
Choose the scope first. If you buy the material, material and freight are included; if the customer supplies the material, only the machining labor is priced. All amounts are in your own currency. Use a period for decimals (e.g. 1250.50); a comma between groups of three digits (1,250) is read as a thousands separator.
2. Machine time and hourly rate
Cycle time: the operator presses Cycle Start, the program runs to the end. If the part needs more than one setup (front and back), add the cycle times together. Load/unload is asked separately so that program improvements and the operator's handling do not get mixed up.
If you do not know your machine hourly rate, see "What is the machine hourly rate?" further down the page: divide your annual machine costs by the productive hours to get the figure without profit.
One-time costs for this job Setup, fixture, programming, special tooling — spent once for this order only
Enter only what is spent for this order; it is divided by the order quantity. Standard vises and regular tools are part of the hourly rate; do not enter them here.
Cutting tool cost Open this for hardened material, expensive inserts (CBN/ceramic) or surfaces with holes and slots; it can stay closed for routine work
On routine jobs, standard insert wear stays inside the hourly rate. But where the insert is expensive or breaks earlier than expected, tooling alone can wreck the price. Enter your estimate here; in sample mode it is compared with what actually happened.
Other costs Outside processing, deburring-washing-packing, expected scrap rate
3. Risk allowance, profit and quote
The risk allowance is not profit: if the stock comes in harder, an insert breaks or the cycle runs long, this reserve is consumed first. If it is not enough, your profit goes next. Keep the two apart.
Cost breakdown (per part)
Who is this calculator for and what does it calculate?
This page is for job shop owners, estimators and production managers who quote CNC machining work, and for students learning how machining cost per part is built up. The tool does not calculate cycle time; you enter it. Deriving time from speeds, feeds and number of passes is a separate calculation, and Mentor CNC has a separate cycle time and cost per part calculator for that. The purpose here is to turn the time and costs you already have into the one number you say to the customer.
The result screen shows material, freight, machining, tooling, the share of one-time costs and outside processing per part; the break-even unit cost; the risk allowance; cost including risk; profit; the unrounded selling price; the rounded quote; the real profit that remains after rounding; and the order totals. The question "I said 43 a part, how much of that is profit?" is answered at a glance.
How is CNC machining cost per part calculated?
The unit cost is the sum of every cost that lands on one part. The calculator adds them in this order:
- Material: blank weight × price per kg or lb, or the price per blank your supplier quoted. If the customer supplies the material this line is zero; the "Customer supplies material (labor only)" option covers that case.
- Freight: the cost of the truck that brought the material is divided by the order quantity. If the material arrives by parcel per part, enter it per part; the tool never divides the same amount twice.
- Machining: machine time per part × machine hourly rate ÷ 60. Machine time is the cycle time (Cycle Start to end of program) plus the load/unload time. At 20 minutes and 75 per hour, machining costs 25.00 per part.
- One-time costs: setup time, programming, fixture and any special tooling bought for this job. These are paid once and divided by the quantity. A 5,000 fixture adds 100 per part on 50 parts and 50 per part on 100; larger batches make the part cheaper.
- Cutting tools: insert price ÷ (number of edges × parts per edge). On routine work this stays inside the hourly rate; with hardened material, expensive inserts or interrupted cuts it must be calculated separately. The shop-floor example below shows why.
- Outside processing and finishing: heat treatment, plating or grinding done by another shop, plus deburring, washing, inspection and packing.
- Scrap: if you expect 5 rejects in 100, you machine about 105 parts to deliver 100 good ones. The material, machine time and inserts of a scrapped part are loaded onto the good parts; fixture, setup and freight are not affected.
The sum of these lines is the break-even unit cost: take the job below this price and every part costs you money.
Quote from the drawing or from a sample?
In small and medium job shops most quotes are made from the technical drawing. The customer sends the drawing, you look at it, say "that is a twenty-minute part" and write the price. It is fast, but a drawing only shows the geometry of the part; it does not show how the part behaves on the machine. In corporate manufacturing and the automotive supply chain the price comes from a sample run: the part is clamped and machined, time and insert consumption are measured, and the price is written from that.
| Method | When to use it | Nature of the result | Suggested risk allowance |
|---|---|---|---|
| Estimate from the drawing | No sample, a fast quote is expected, low quantity | Estimated quote | 10% or more |
| Sample run data | Repeat work, medium and high quantity, hard or expensive material | Verified quote | About 5% |
| Pilot batch / production data | High volume, ongoing work; after the first batch has been run | Actual cost | According to the real deviation |
In sample mode the time of a single part is never used on its own. The first part includes setup, measuring and trial cuts; the third part comes off faster. That is why the tool asks for the total working time, deducts the setup time and divides the rest by the number of good parts. If ten samples took 120 minutes, the average is 12 minutes; the tool also shows the optimistic (10.8 min) and safe (13.2 min) bounds next to it.
Risk allowance and profit are not the same thing
The most common quoting mistake is to squeeze uncertainty into the profit percentage. The shop that says "I put twenty percent on it, if something comes up we cover it from there" watches its profit melt when a problem appears, but cannot see what exactly melted. The calculator shows the two on separate lines:
| Item | Amount |
|---|---|
| Calculated unit cost | 900.00 |
| Production risk allowance 10% | 90.00 |
| Cost including risk | 990.00 |
| Profit 20% | 198.00 |
| Calculated selling price | 1,188.00 |
| Quote rounded up to the nearest 100 | 1,200.00 |
When something goes wrong in production the risk allowance is consumed first; only when it runs out does profit start to shrink. There is a long "lost profit" zone before you reach an outright loss, and most shops do not notice they are in it. A separate risk allowance makes that zone visible.
Markup on cost or margin on selling price?
"Thirty percent profit" can mean two different things. On the shop floor most people mean multiplying the cost by 1.30; in accounting it means thirty percent of the selling price is profit. The two do not give the same number:
| Cost | Rate | Method | Selling price | Profit share of price |
|---|---|---|---|---|
| 1,000 | 30% | Markup on cost (× 1.30) | 1,300.00 | 23.1% |
| 1,000 | 30% | Margin on selling price (÷ 0.70) | 1,428.57 | 30.0% |
The calculator defaults to markup on cost, in line with shop practice, and offers margin on selling price as an option. Rounding is applied only to the final price, intermediate figures stay exact, and the tool reports how much profit is really left inside the rounded price.
What is the machine hourly rate and how do you find it?
The most important input of this calculator is the machine hourly rate, often called the shop rate. The figure you quote as "my rate is 75 an hour" contains machine depreciation, electricity, maintenance, standard inserts and consumables, a share of rent and overhead and, in most shops, the operator's wages. In short: what does one hour of this machine cost you? Total annual costs are divided by the machine's real productive hours per year. Not shift hours, but hours that actually earn money: holidays, maintenance, breakdowns, setup and idle waiting are deducted. If only 70% of 2,000 planned hours are productive, the costs are divided by 1,400 hours; skip this correction and the hourly rate comes out too low, and every quote quietly loses money.
If you do not know your rate, use the Mentor CNC machine hour rate calculator, which walks through the calculation step by step; otherwise enter an estimate without profit and verify it against your annual costs afterwards.
From the shop floor: in a corporate plant the price never came from the drawing
The founder of Mentor CNC started his career at a corporate supplier machining parts for the automotive industry. When a technical drawing arrived there, nobody ever quoted from the drawing. The die, the fixture, the casting: everything arrived ready. We clamped the part on the CNC, machined it, worked out the time, the tooling cost, the downtime and the insert-change time, and quoted accordingly. Then the company that had sent the sample would say: "No, that price is wrong, it has to be this much; your fixture or your machining method is wrong." We were baffled. It turned out the part had already been machined by the automotive manufacturer itself; they had their times and were asking us for a price against that knowledge.
The lesson is this: on a thousand-part job, not all thousand parts come off in three minutes. With commercial bar stock some bars come long, some short; some hard, some soft; now and then there is slag in the material; on one part an insert drops off and has to be fished out of the machine. Downtime is never constant. The part you looked at and called "five minutes" can come off in three or in seven. The part you measured at 12 minutes on ten samples can drop to 9 minutes over two thousand parts through improvements, or climb to 15 for the reasons above. These differences are small, but over a year they eat profit. So the Mentor CNC advice is clear: machine a sample whenever you can, and look at the raw material with your own eyes. If you must quote from the drawing, calculate carefully and think about what can go wrong, but do not price yourself out of the job either. Not doing a sample has that cost too: you may inflate a ten-minute part to fifteen in your head, quote too high and lose the work.
From the shop floor: the CBN insert, the drilled disc and the drawing-based price that turned into a loss
A second example, this time from a small job shop. We were to machine a hardened, disc-shaped part that looked like a brake disc. Because the material was hard, a CBN insert was planned. The owner quoted, at the prices of the day, 50 per part. The arithmetic was: a CBN insert costs 25, it has two edges, each edge should make ten parts; so twenty parts per insert and 1.25 tooling cost per part.
The parts arrived and we clamped them on the lathe. The surface to be machined had three holes in it. The CBN edge left the material at every hole and re-entered with an impact after each one. The first edge broke within a few parts. We indexed to the second edge; it broke too. We changed speed and feed, tried different settings; in the end we used four CBN inserts on fifteen parts. A job that should have taken half a day took two and a half, and it lost money.
| Item | Assumed in the quote | What actually happened |
|---|---|---|
| Parts per insert | 20 (2 edges × 10) | 3.75 (15 parts ÷ 4 inserts) |
| Tooling cost per part | 1.25 | 6.67 |
| Difference | — | about 5.3×, +433% |
| Tooling cost over 200 parts | 250 | about 1,333 |
| Machine occupied | half a day | two and a half days |
The problem was not that "CBN cannot machine hard material". The problem was that nobody had checked on a sample whether that CBN grade, edge geometry and cutting data could take such a heavy interrupted cut. The "Cutting tool cost" section of the calculator and its cutting-condition checkboxes exist precisely for this: when hardened material, a surface with holes and a CBN/ceramic insert are ticked together, the tool warns you not to quote before machining a sample; in sample mode it puts your estimated tooling cost side by side with the actual figure.
Why interrupted cutting and hard material wreck a quote
On a surface with holes, slots or keyways the edge does not cut continuously; after every gap it strikes the material again. This is interrupted cutting. Carbide inserts tolerate the impact to a degree; CBN and ceramic inserts give an excellent finish in hard material under the right conditions but are brittle under impact. The tool life printed in the catalog is for continuous cutting and no longer applies. When quoting this kind of work, do three things: take tooling out of the hourly rate and calculate it separately, raise the risk allowance, and if at all possible machine a few sample parts and count the inserts you use.
What to do on high-volume jobs
A sample is not one hundred percent certain either; ten parts do not guarantee the behavior of a thousand. Bar length and hardness vary within a batch, an insert breaks earlier than expected, chips wrap, a dimension drifts, the fixture gets dirty. For high volumes the recommended route is: machine a sample and prepare a provisional quote; run a pilot batch of the first hundred parts; measure the real time, insert consumption and scrap rate; confirm or revise the price. The "From sample / pilot batch data" mode of this tool works with pilot batch results as well: enter the total time, good parts and inserts used for the hundred parts and see the actual cost.
Frequently asked questions
Where do I put the operator's wages?
Most shops quote a machine hourly rate that already includes the operator. If so, leave "Operator cost is included in the hourly rate" ticked. If you track the operator separately, untick it and enter the operator's fully loaded hourly cost; the tool adds it to both the machining time and the setup time.
What changes when the customer supplies the material?
Choose "Customer supplies material (labor only)". Material and freight are excluded and only labor is priced. Because you do not control the quality of customer-supplied stock, do not set the risk allowance too low.
Should I enter standard insert wear separately?
No. On ordinary steel, aluminum and cast iron work, standard insert consumption is part of the machine hourly rate; entering it again inflates the price. Open the tooling section only for expensive inserts, hardened material, interrupted cutting or special tooling bought for this job.
Is tax included?
No. Every figure in the calculator is before VAT or sales tax. Enter material prices and the hourly rate net of tax and add tax to the quote separately.
Does rounding change my profit?
Yes, rounding up raises the price slightly. That is why the tool separately reports the profit that really remains inside the rounded price. If you want negotiating room, choose a larger rounding step.
Why is the price so different for 50 and 500 of the same part?
One-time costs such as fixture, setup and programming are divided by the quantity. A fixture that adds 100 per part on 50 parts adds 10 per part on 500. When giving tiered prices, run the calculator once for each quantity.
Which currency does the calculator use?
None in particular. Enter every figure in your own currency and the results come out in the same currency. Only the weight unit has to be consistent: if you enter the blank weight in kilograms, use the price per kilogram; if in pounds, the price per pound.
Mentor CNC note and disclaimer
This tool is a quoting aid; it does not produce a definitive cost. Tolerances, surface finish, number of setups, raw material quality, machine condition and operator experience change the real time and tool consumption. A price given from the drawing is an estimate; machine a sample whenever possible and, on high volumes, re-check the actual cost after the first batch. Mentor CNC accepts no responsibility for quotes based on this calculation or for their commercial consequences.