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What Is Contribution in Business? Definition, Formula & Worked Example

Contribution is the money a sale brings in after paying the costs that exist only because of that sale. It is called contribution because it contributes, first, towards the business's fixed overheads — and once those are covered, towards profit.

Contribution Defined

Every business has two kinds of cost. Variable (or direct) costs rise and fall with each unit sold — materials, direct labour, packaging, payment fees, delivery. Fixed costs stay the same however much you sell in the short term — rent, rates, insurance, salaried staff, software subscriptions.

Contribution is what is left of the selling price once the variable costs of that sale are paid. It ignores fixed costs entirely, which is exactly what makes it useful: it tells you what each extra sale is worth to the business.

Selling Price − Variable Cost
Contribution per unit
Contribution ÷ Sales
Contribution margin ratio

Use prices excluding VAT. VAT you charge a customer is collected on HMRC's behalf, not income the business keeps — see our VAT registration guide.

Worked Example: Making and Selling Chairs

A small workshop makes and sells chairs at £50 each. For every chair sold, it incurs these direct costs:

Selling price£50
Wood£10
Direct labour£5
Glue£2
Varnish£2
Total variable cost£19
Contribution per chair (£50 − £19)£31
Contribution margin ratio (£31 ÷ £50)62%

Each chair sold puts £31 towards the workshop's fixed costs. Put the other way, 62p of every pound of chair sales is available to pay overheads and then become profit.

Contribution Is Not Profit

The most common mistake is treating contribution as profit. Contribution only deducts variable costs; profit deducts everything. Suppose the workshop's fixed costs — rent, rates, insurance and its owner's drawings — come to £3,100 a month:

  • Sell 80 chairs: total contribution £2,480, fixed costs £3,100 — a £620 loss, even though every single chair made a positive contribution.
  • Sell 100 chairs: total contribution £3,100 — exactly breaking even.
  • Sell 130 chairs: total contribution £4,030 — a £930 profit.

Once fixed costs are covered, the whole contribution from each further sale is profit. This is why businesses with high fixed costs become very profitable quickly once they pass break-even — and lose money quickly below it.

Using Contribution to Find Break-even

Contribution gives the quickest route to a break-even point:

Break-even units = Fixed Costs ÷ Contribution per Unit
£3,100 ÷ £31 = 100 chairs a month

For a business selling many different products, use the contribution margin ratio instead: break-even sales = fixed costs ÷ contribution margin ratio. At 62%, the workshop needs £3,100 ÷ 0.62 = £5,000 of sales a month. Our break-even calculation guide works through more examples, and your break-even figure should feed directly into your cash flow forecast.

Contribution and Pricing Decisions

Contribution is the basis of contribution pricing. Imagine the workshop is already selling 100 chairs a month, so its fixed costs are covered, and a hotel offers to buy 40 extra chairs at £35 each — well below the normal £50.

On a full-cost view the order looks unattractive. On a contribution view, each chair still adds £35 − £19 = £16, so the order adds £640 of profit, because the rent and other overheads are already paid. As long as the price is above variable cost, the extra sale increases profit.

That logic has real limits: the special price may leak to regular customers, the workshop may not have spare capacity (extra labour or overtime raises the variable cost), and repeatedly selling near variable cost leaves nothing to cover overheads if regular sales fall. Our guides to the practical points in contribution pricing, how overheads fit into pricing decisions and pricing decisions cover these in detail.

Common Mistakes

  • Including VAT in the selling price — a sixth of a 20%-VAT-inclusive price belongs to HMRC, and the whole of that error lands on contribution. On the £50 chair sold at £60 including VAT, using £60 would show £41 of contribution instead of £31.
  • Leaving out smaller variable costs — card payment fees, marketplace commission, packaging and delivery are all variable and add up quickly, especially online.
  • Treating stepped costs as fixed — an extra member of staff or a second van is "fixed" only until volume forces you to add another one.
  • Forgetting your own time — if you make the product yourself, a realistic rate for your labour belongs in variable cost, or your contribution figure flatters the business.
  • Confusing contribution with gross profit — gross profit in a set of accounts often includes some costs that do not vary with each sale, so the two figures rarely match exactly.

Frequently Asked Questions

Contribution is the money a sale brings in after paying the costs that only exist because of that sale (its variable or direct costs, such as materials and direct labour). It is called contribution because that money contributes first towards the business's fixed overheads, such as rent and salaries, and once those are covered, towards profit.

Contribution per unit = selling price per unit − variable cost per unit. Total contribution = total sales − total variable costs. Both figures should use prices excluding VAT, because VAT collected is not income the business keeps.

Contribution only deducts variable costs. Profit deducts all costs, including fixed overheads such as rent, insurance and salaries. A product can make a healthy contribution on every sale while the business as a whole still makes a loss, if total contribution is not yet large enough to cover the fixed costs.

The contribution margin ratio is contribution divided by sales, shown as a percentage. If a product sells for £50 and has £19 of variable costs, its contribution is £31 and its contribution margin ratio is 62% — meaning 62p of every pound of sales goes towards fixed costs and profit.

Break-even point in units = fixed costs ÷ contribution per unit. If fixed costs are £3,100 a month and each sale contributes £31, the business needs to sell 100 units a month to break even. Every sale beyond that turns its full contribution into profit.

Contribution pricing means judging whether a sale is worth making by whether it adds contribution, rather than by whether it covers a full share of overheads. If fixed costs are already covered, an extra order priced above its variable costs still increases profit. It needs care in practice — see our guide to the practical points in contribution pricing.