How Business Discounts Affect Profit

A discount looks like a small concession and behaves like a large one. Twenty per cent off a price sounds like giving away a fifth of the sale; in practice it often gives away half the profit, because the cost of the goods does not move when the price does.

This guide works through the arithmetic, shows how much extra volume a discount demands, and sets out the narrow conditions under which discounting is a sensible decision rather than an expensive habit.

A discount comes straight out of profit

Costs are unaffected by the price you charge. The supplier still wants the same amount, the materials still cost the same, and the hours still have to be worked.

So every pound of discount comes out of profit, not revenue. That is what makes the effect so much larger than it looks.

At a price of 250 with a cost of 150, the profit is 100. A 20 per cent discount reduces the price by 50 to 200. The cost remains 150, so profit falls to 50.

Half the profit, from a discount that reads as a fifth.

The margin maths

The size of the damage depends on the margin you started with. A business with a high margin can absorb a discount; a business with a thin one cannot.

The formula: new profit = price × (1 - discount) - cost.

At 250 and 20 per cent: 250 × 0.80 = 200, minus 150 = 50.

As a percentage of the new price, the margin falls from 40 per cent to 25 per cent: the discount cut the price by 20 per cent and the margin by 15 percentage points.

Push the discount further and the arithmetic becomes brutal. At 30 per cent, the price is 175 and the profit is 25, a 75 per cent fall from a further 10 points of discount. At 40 per cent, the price is 150 and the profit is zero. The business is working for nothing, and every sale adds cost without contribution.

How much extra volume a discount demands

A discount only pays if it brings enough additional sales to recover the profit given up. That volume is usually far higher than the discount suggests.

If the old profit per unit was 100 and the new profit per unit is 50, you need twice the volume just to stand still. Not 20 per cent more — double.

The general formula: required volume increase = (original profit / new profit) - 1.

• At 10 per cent off: price 225, profit 75, required increase 33 per cent.
• At 20 per cent off: price 200, profit 50, required increase 100 per cent.
• At 30 per cent off: price 175, profit 25, required increase 300 per cent.

A 20 per cent discount needs double the sales to make the same money. Most businesses cannot double their volume in the period the discount runs.

When discounts make sense

Discounting is a tool, and like any tool it works when used deliberately for a specific purpose.

• Clearing stock that will not sell. The alternative is holding cost and eventually a write-off. A price below the normal one may still beat both.
• Filling a slow period. If capacity would otherwise be idle and the price still covers variable costs, a discounted sale contributes something rather than nothing — provided it does not displace full-price work.
• Prepayment. A discount in exchange for payment upfront is really a finance cost, and often a cheap one compared with borrowing.
• Large volume with lower unit costs. If a big order genuinely reduces your cost per unit, sharing some of that saving can be rational. Check that the cost actually falls.
• A first order from a new customer. A one-off introductory price can be justified if the lifetime value is real and the discount is not repeated.

What does not work is a discount offered because a customer asked. That is a price cut with a story attached.

Alternatives to a headline discount

Often what the customer wants is not a lower price but a lower number on the invoice. There are cheaper ways to provide it.

• Reduce the scope. Fewer deliverables at the same rate protects your margin and gives the customer a genuine choice.
• Change the payment terms. A smaller deposit or staged payments may solve their cash-flow concern without touching the price.
• Offer a time-limited price. A price held for 14 days creates urgency without permanently resetting your rate.
• Say no. If the work is not viable at the price, declining is cheaper than delivering at a loss and discovering it at the end.

Common mistakes

• Confusing a discount with a proportional cut in profit. Twenty per cent off a product carrying a 40 per cent margin does not remove 20 per cent of the profit — it removes half.
• Assuming volume will cover it. The volume needed is usually double or triple, not a fifth more.
• Discounting without a limit. "See what you can do" becomes a permanent rate.
• Forgetting the costs that scale. A discount that assumes fixed costs will not rise is fine until the extra volume requires another hire.
• Discounting to match a competitor. You do not know their cost base; matching their price may mean matching their loss.

Checking before you concede

Run the proposed price through the discount calculator to see the effect on revenue and the new profit figure, then check the margin with the profit margin calculator. If the discount still leaves a margin you can defend, it is a choice. If it leaves 5 per cent, it is a bet — and one the business may not be able to afford.