Skip to main content
ScotlandBusiness ManagementSyllabus dot point

What are fixed and variable costs, and how does a business calculate its break-even point and margin of safety?

The difference between fixed and variable costs and total costs, the meaning and use of the break-even point and break-even chart, the calculation of the break-even point using contribution, and the meaning of the margin of safety.

A focused answer to the SQA National 5 Business Management content on costs and break-even, covering fixed, variable and total costs, the break-even point and break-even chart, calculating the break-even point using contribution, and the margin of safety.

Generated by Claude Opus 4.811 min answer

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

Have a quick question? Jump to the Q&A page

Jump to a section
  1. What this dot point is asking
  2. Types of cost
  3. The break-even point
  4. The break-even chart
  5. The margin of safety
  6. Why break-even matters
  7. Try this

What this dot point is asking

The SQA wants you to know the types of cost, calculate the break-even point using contribution, read a break-even chart, and work out the margin of safety. This is a calculation topic, so practise the formulae until they are automatic.

Types of cost

To understand profit, a business splits its costs into two kinds.

The break-even point

The break-even point is the level of output and sales where total revenue equals total costs, so the business makes no profit and no loss. Selling more than this makes a profit; selling less makes a loss.

The key idea is contribution: the amount each unit sold contributes towards covering the fixed costs.

Once contribution per unit has paid off all the fixed costs, every further unit is profit.

The break-even chart

A break-even chart shows the same information as a graph, with output (units) on the horizontal axis and money (pounds) on the vertical axis. It plots three lines:

  • Fixed costs: a horizontal line, the same at every level of output.
  • Total costs: starts at the fixed-cost level and rises as variable costs are added.
  • Total revenue (sales): starts at zero and rises with each unit sold.

The point where the total revenue line crosses the total costs line is the break-even point. To the left of it the firm makes a loss (costs above revenue); to the right it makes a profit (revenue above costs).

The margin of safety

The margin of safety shows how far sales can fall before the business starts to make a loss. It is the gap between actual (or expected) sales and the break-even point.

A large margin of safety means lower risk, because sales can drop a long way before a loss is made. In the candle example, if the maker actually sells 500 candles, the margin of safety is 500−300=200500 - 300 = 200 candles: sales could fall by 200 before the firm fails to break even.

Why break-even matters

Break-even analysis helps a business: see the minimum sales needed to avoid a loss, set sales targets, judge whether a price or a new product is worthwhile, and assess risk through the margin of safety. It is a planning tool, though it assumes prices and costs stay constant, which is not always true.

Try this

Q1. State the difference between a fixed cost and a variable cost. [2 marks]

  • Cue. A fixed cost stays the same whatever the output (rent); a variable cost rises with output (materials).

Q2. A product sells for £10\pounds 10, variable cost is £6\pounds 6, fixed costs are £2000\pounds 2000. Calculate the break-even point. [3 marks]

  • Cue. Contribution =10−6=£4= 10 - 6 = \pounds 4; break-even =2000÷4=500= 2000 \div 4 = 500 units.

Q3. If the firm in Q2 sells 650 units, calculate the margin of safety. [2 marks]

  • Cue. 650−500=150650 - 500 = 150 units.

Exam-style practice questions

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

SQA-style Calculate4 marksA firm sells a product for £20\pounds 20. Variable costs are £12\pounds 12 per unit and fixed costs are £4000\pounds 4000. Calculate the break-even point and the margin of safety if the firm sells 700 units.
Show worked answer →

Award marks for the contribution, the break-even point and the margin of safety. Contribution per unit == selling price −- variable cost =20−12=£8= 20 - 12 = \pounds 8 (1). Break-even point == fixed costs ÷\div contribution per unit =4000÷8=500= 4000 \div 8 = 500 units (1). The margin of safety is actual sales −- break-even sales =700−500=200= 700 - 500 = 200 units (1), meaning sales could fall by 200 units before the firm makes a loss (1). Markers reward the correct contribution, the break-even figure and the margin of safety with units.

SQA-style Explain3 marksExplain the importance of the break-even point to a business.
Show worked answer →

Award marks for explained reasons (a use and its benefit), up to 3. The break-even point tells the business how many units it must sell to cover all its costs, so it knows the minimum level of sales it must achieve to avoid a loss (1). It helps the business set sales targets and judge whether a product or price is worthwhile before committing (1). It shows the margin of safety, how far sales can fall before a loss is made, which helps the firm assess risk and plan (1). Markers reward the link between break-even and a useful business decision such as target setting or assessing risk.

Related dot points

Sources & how we know this