Cost Per Part Calculator
The cost to make one part — material, labour, machine time, tooling amortised over the run and overhead — and how the unit cost falls as the batch grows.
Unit cost has two kinds of component.
How the cost per part calculator works
Unit cost has two kinds of component. Material, labour and machine time scale with each part. Tooling and setup are paid once per run, and their share per part falls as the run grows — which is why a quote for 100 and a quote for 10,000 differ by far more than the material.
The break-even quantity shows where the fixed costs stop dominating: below it, the setup is the price; above it, the part is.
Formula: unit cost = variable per part + (tooling + setup) / quantity + overhead
Worked examples
| Inputs | Cost per good part | Note |
|---|---|---|
| A run of 500 | 18.009 | setup is a fifth of the cost |
| A run of 50 | 45.8441 | setup dominates |
| A run of 5,000 | 15.2255 | close to the variable cost |
FAQFrequently asked questions
How is cost per part calculated?
Material plus machine time plus labour per part, plus the run's setup and tooling divided by the quantity, plus overhead — then loaded for the parts that get scrapped.
Why does a bigger order cost less per part?
Because setup and tooling are paid once and spread over more parts. Below the break-even quantity the setup is most of the price.
What machine rate should I use?
The fully burdened hourly cost — depreciation, power, maintenance, floor space and the operator if not counted separately. Sixty to two hundred an hour covers most machine tools.
How does scrap affect the price?
You pay to make every part but sell only the good ones, so the good-part cost is divided by the yield. Three per cent scrap adds about three per cent to the price.
Should overhead be a percentage?
It is the common convention. Activity-based costing is more accurate and far more work; a percentage is right for a quote.
Where these figures come from
- Nakajima (1988) — Introduction to TPM — the origin of Overall Equipment Effectiveness and its six big losses
- Safe Work Australia — the national work health and safety body
Last checked: September 2026. Definitions follow standard operations-management practice; where plants commonly differ, the page says so.