Model the cost per unit of a real manufacturing process from materials, labour and overhead, watch the numbers update live as you edit, and see how batch scale changes the economics. Toggle on a selling-price model if you want to explore margin and pricing too. Prefer an itemised, line-by-line cost sheet instead? Try the OPEX calculator.
Operating Cost (OPEX) is the total recurring cost of producing one unit of product: the sum of materials, labour and overhead. Where Raw Material Cost (RMC) isolates the materials line, OPEX rolls all three cost pillars into a single per-unit figure, and lets you see how they trade off against each other and against production scale.
| Symbol | Term | Units |
|---|---|---|
| $C_{\text{materials}}$ | $\sum_i q_i c_i (1+s_i)$ — quantity $q_i$ × unit cost $c_i$ of material $i$, inflated by its scrap fraction $s_i$ | currency / unit |
| $C_{\text{labour}}$ | $h\,r\,(1+b)$ — labour hours $h$ per unit × rate $r$, inflated by benefits multiplier $b$ | currency / unit |
| $C_{\text{overhead}}$ | $\dfrac{F}{N} + v$ — fixed monthly overhead $F$ spread across batch size $N$, plus variable overhead $v$ per unit | currency / unit |
Scrap cost is shown separately in the dashboard: it is the financial expression of the same waste an E-factor measures in mass, reducing it lowers cost and environmental burden together.
OPEX is one of several economic lenses in the toolkit alongside Raw Material Cost (RMC), Cost Effectiveness, and Capital Efficiency. RMC is the materials line item inside OPEX; OPEX adds labour and overhead to give the full recurring cost of production.
| Metric | What it measures | Stage |
|---|---|---|
| RMC | Total raw material cost per unit mass of product | Materials |
| OPEX | Ongoing operating cost per unit product, including materials, labour, and overhead | Operations |
| Cost Effectiveness (CE) | Value or output achieved relative to total cost incurred | Operations |
| Capital Efficiency (CapE) | Return generated relative to capital invested in plant and equipment | Investment |
Everything below recalculates live as you type — no calculate button. The right-hand panel stays in view while you edit inputs on the left.
Enter each material per unit of product: reagents, solvents, catalysts, components, packaging. Scrap rate inflates the line cost to reflect real-world loss/rework.
| Material name | Category | Qty / unit | Unit cost (£) | Scrap (%) | Line cost (£) |
|---|
Direct labour time and cost to produce one unit.
Fixed overhead is spread across the batch; variable overhead is charged per unit regardless of scale.
| Line item | Category | Cost (£/unit) | % of OPEX | Visual |
|---|---|---|---|---|
| Enter materials, labour and overhead above to see the breakdown. | ||||
Sessions are stored in your browser only. No data leaves your device.
Export your OPEX model as a PDF report or CSV data file. PDF opens in a new tab and uses your browser's print function. Selling-price figures are only included if the toggle above is on.
Roles follow the CRediT taxonomy, adapted for educational software. Hover a contributor's name for a summary, or a column header for the role definition.
| Contributor |
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