How to estimate CNC machining cost
Methodology — 8 November 2026. Transparent planning assumptions; not automated toolpath analysis.
Quoting a CNC milling job involves the material you purchase, machining and operator time, fixed setup work, expected waste, overhead and a margin on the final selling price. FabCost Desk separates these costs so shop owners can change their assumptions and explain the result to customers.
1. Calculate the starting stock
The free beta models a solid rectangular blank. Starting stock dimensions are the finished part bounding dimensions plus twice the allowance on each axis. Material mass is length_mm × width_mm × height_mm × density_kg/m³ ÷ 1,000,000,000. Multiply by your real stock price per kilogram.
This is a whole-blank material purchasing model, not finished part volume, CAD solid mass or a chip-recycling credit.
2. Estimate variable and batch costs
For each expected blank, machining cost is cycle_minutes ÷ 60 × machine_hourly_rate. Operator labor, tooling, packaging and finishing are additional input costs. The application models expected production blank count as finished_quantity ÷ (1 − scrap_rate). That is an expected-value estimate rather than a commitment to buy a fractional blank.
One-time setup is calculated separately as setup_minutes ÷ 60 × machine_hourly_rate. A shop's machine hourly rate may already include operator labor. If it does, enter zero for separate manual labor to avoid charging twice.
3. Add overhead and profit margin
Overhead percentage applies to total direct cost. The suggested price divides cost by 1 − target_margin / 100. For example, at a 25% margin, a $300 cost yields a $400 proposed selling price and $100 estimated gross profit, which is 25% of selling price.
This is a margin model, not a 25% markup on cost. Use your own currency: the currency switch only changes the displayed symbol; it does not convert money with an exchange rate.
4. Compare quantities
The quantity table recalculates the same job at several lot sizes, including your selected quantity. The one-time setup is distributed over more pieces, so the price per part generally declines. The figures are not customer discounts and do not assume future improvements in cycle time, materials procurement or capacity.
5. Check the estimate
Verify against CAM simulations, actual production history, stock sizes, cut-off and clamping allowances, fixtures, minimum order charges, scrap handling, inspection, tolerances, tooling wear, outside processes, shipping and taxation. No STEP, STL, DXF or other drawing is uploaded or analyzed by this beta.
Example
A batch with an estimated direct cost of $400, 10% overhead and 20% target margin produces a suggested quote of $550 (cost $440 divided by 0.8). Actual numbers are always dependent on shop inputs.