EnglandDesign and TechnologySyllabus dot point

How does a designer calculate material quantities, waste and the cost of making a product?

Costing and quantities: calculating material quantities and waste, percentage and percentage change, nesting and yield, material and labour cost, profit and selling price, and break-even, with units carried through the working.

A focused answer to Eduqas A-Level Product Design on costing and quantities: calculating material quantities and percentage waste, nesting and yield, material and labour cost, profit, selling price and break-even, with worked calculations and units carried through.

Generated by Claude Opus 4.812 min answerUpdated 2026-06-02

Reviewed by: AI editorial process; not yet individually human-reviewed

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Quick answer

Costing turns a design into money. Material quantity is found from the yield (parts per sheet or per length) and nesting (how parts are laid out to fit the most in). Percentage waste is $\frac{\text{wasted area}}{\text{total area}} \times 100$ , and percentage change is $\frac{\text{change}}{\text{original}} \times 100$ . Material cost per part is the stock cost divided by the yield; total cost is material plus labour (plus overheads). Profit is selling price minus total cost; the selling price is the cost plus a profit margin. Break-even is the number of sales at which income covers all costs (fixed plus variable). Always show the working and keep the units (pounds, square millimetres, percentages), because they carry marks, and use $\pi r^2$ and area formulae correctly when finding quantities and waste.

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What this dot point is asking
Quantities, yield and nesting
Percentage and percentage waste
Material cost, labour, profit and selling price
Break-even

What this dot point is asking

Eduqas wants you to calculate material quantities and waste, use percentages and percentage change, work out material and labour cost, profit, selling price and break-even, and carry units through the working. Costing is the commercial maths of the paper: a calculator is allowed, working and units carry marks, and at least one calculation is usually a full worked problem, so accuracy and method matter.

Quantities, yield and nesting

Key fact

Material quantity is how much stock a job needs, found from the yield, the number of parts that fit in a sheet, length or volume. For flat parts, the yield depends on nesting, the arrangement of the parts on the sheet to fit the most and waste the least: a simple grid gives a round number ( $\frac{\text{sheet length}}{\text{part length}} \times \frac{\text{sheet width}}{\text{part width}}$ ), while a staggered (offset) nest interlocks rows to fit more, especially for circles and irregular shapes. Choosing a stock form close to the part size, and nesting well, reduces the material used per part. Yield links directly to cost, because the material cost per part is the stock cost divided by the yield, so a better nest lowers the unit cost.

Percentage and percentage waste

Definition

Percentage maths runs through costing. A percentage is a fraction out of 100: a value as a percentage of a total is $\frac{\text{value}}{\text{total}} \times 100$ . Percentage waste is the wasted material as a percentage of the stock used: $\text{waste \%} = \frac{\text{wasted area (or mass)}}{\text{total area (or mass)}} \times 100$ , where the wasted area is the stock area minus the used (part) area. Percentage change (for example a price rise or a saving) is $\frac{\text{change}}{\text{original value}} \times 100$ , and a percentage increase or decrease of a value is found by multiplying by $(1 \pm \frac{\text{percent}}{100})$ . Getting the denominator right (always the original or total) is the commonest source of error, so identify what the percentage is "of" before dividing.

Material cost, labour, profit and selling price

Break-even

The break-even point is the level of sales at which total income equals total cost, so the product starts to make a profit beyond it. Costs split into fixed costs (which do not change with output, such as tooling, premises and machinery) and variable costs (which rise with each unit, mainly material and labour). The break-even quantity is the fixed costs divided by the contribution per unit, where the contribution is the selling price minus the variable cost per unit: $\text{break-even} = \frac{\text{fixed costs}}{\text{selling price} - \text{variable cost per unit}}$ . Break-even links to scale of production, because high tooling (a large fixed cost) needs a high break-even volume to be worthwhile, which is why expensive processes such as injection moulding only pay off at high volume. A strong answer can compute a break-even and interpret it.

Costing a product and finding waste

Find the yield and material cost per part

A £24 sheet yields parts in a grid: along the length $\frac{2000}{250} = 8$ and across the width $\frac{1000}{200} = 5$ , so the yield is $8 \times 5 = 40$ parts. Material cost per part is $\frac{24}{40} = £0.60$ .

Find the total cost per part

If labour is £1.20 per part and overheads add £0.40, the total cost per part is $0.60 + 1.20 + 0.40 = £2.20$ .

Set a selling price and profit

With a 50 percent markup on cost, the selling price is $2.20 \times 1.5 = £3.30$ , so the profit per part is $3.30 - 2.20 = £1.10$ .

Find the percentage waste

If each part is $250$ mm by $200$ mm $= 50\,000$ square mm and the sheet is $2000 \times 1000 = 2\,000\,000$ square mm, the used area is $40 \times 50\,000 = 2\,000\,000$ square mm, so a perfect grid wastes $0\%$ here; if the parts were discs, the rounded corners would be waste, found by $\frac{\text{sheet area} - \text{total part area}}{\text{sheet area}} \times 100$ . State the working and units throughout, because they carry the marks.

Exam-style practice questions

Practice questions written in the style of WJEC Eduqas exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Eduqas 20204 marksA sheet of material costs £18 and yields 24 finished parts. The labour to make each part is £1.50. Calculate the total cost to make one part, and the material cost as a percentage of that total.

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A Component 1 costing calculation. Marks for the material cost per part, the total, and the percentage.

Material cost per part is the sheet cost divided by the yield: $\frac{18}{24} = £0.75$ . Total cost per part is material plus labour: $0.75 + 1.50 = £2.25$ . The material cost as a percentage of the total is $\frac{0.75}{2.25} \times 100 = 33.3\%$ (to one decimal place).

Award marks for $£0.75$ material, $£2.25$ total, and $33.3\%$ . A common dropped mark is dividing by the wrong number or forgetting to add labour. Always show the working and keep the pounds.

Eduqas 20226 marksA rectangular sheet measures 2400 mm by 1200 mm. Discs of diameter 200 mm are cut from it in a grid. Calculate how many discs fit, the percentage of material wasted, and suggest one way to reduce the waste.

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A Component 1 nesting and percentage-waste calculation. Marks for the number of discs, the waste percentage and the improvement.

In a simple grid, each disc needs a 200 mm by 200 mm cell. Along the length: $\frac{2400}{200} = 12$ ; along the width: $\frac{1200}{200} = 6$ ; so $12 \times 6 = 72$ discs. Sheet area $= 2400 \times 1200 = 2\,880\,000$ square mm. Area of one disc $= \pi r^2 = \pi \times 100^2 = 31\,416$ square mm; total disc area $= 72 \times 31\,416 = 2\,261\,952$ square mm. Waste $= 2\,880\,000 - 2\,261\,952 = 618\,048$ square mm, which as a percentage is $\frac{618\,048}{2\,880\,000} \times 100 = 21.5\%$ .

One way to reduce waste: nest the discs in a staggered (offset) pattern so rows interlock, fitting more discs per sheet. A top answer shows the count, the waste percentage and a sensible nesting improvement.

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Sources & how we know this

Eduqas A Level Design and Technology specification (Product Design) — Eduqas (2017)