The Discount Trap: The Maths Nobody Does

A 10% discount sounds trivial. Most owners give them without thinking twice. But the maths of discounting is brutal, and almost nobody does it before agreeing to one.

Discounting feels like a minor goodwill gesture. The arithmetic says otherwise. Because a discount comes straight out of your profit, not your revenue, even a small one demands a surprisingly large jump in sales just to break even.

A discount doesn't come out of the price. It comes out of the profit.

This is the misunderstanding at the heart of it. Say you sell something for £100 that cost you £60, so you make £40. Knock 10% off the price and you haven't lost 10% of something vague, you've lost £10 off your £40 of profit. That's a full quarter of what you were making, on every single sale. The cost of the goods doesn't move. The whole discount lands on the one part of the deal that was yours to keep.

That's why discounting is so much more dangerous than it feels. A 10% cut to the price is a 25% cut to the profit in that example, and the thinner your margin to start with, the worse the ratio gets.

The number nobody calculates

Every discount comes with a hidden price tag: the extra sales you now need just to make the same total profit as before. It's easy to work out, and almost nobody does it. The extra volume you need is the discount divided by what's left of your margin after it:

Extra sales needed = discount ÷ (margin − discount)

On a 40% margin, a 10% discount leaves you 30%. So you need 10 ÷ 30 = 33% more sales just to make the same profit you made before. Not 10% more. A third more. And it gets steeper as margins thin:

50% margin, 10% discount → +25% sales just to break even

40% margin, 10% discount → +33%

30% margin, 10% discount → +50%

40% margin, 20% discount → +100%

30% margin, 20% discount → +200%

A 20% discount on a 30% margin means you must sell three times as much to end up where you started. That isn't a promotion. It's a fire sale you haven't noticed.

Why the volume rarely comes back

Here's the quiet tragedy. You almost never gave the discount in order to triple your sales. You gave it to win one deal, shift some ageing stock, or keep one customer happy. So the extra third, or extra double, that the maths demands was never going to appear. The discount doesn't buy volume. It just hands back profit you'd already earned. Worse, it trains customers to wait for the next deal and quietly resets what they think your work is worth.

What to do instead of cutting the price

The aim isn't to never discount. It's to never discount blind, and to reach for the price lever last rather than first.

Add value before you cut price, throw in something that costs you little but is worth a lot to them. Hold the price and explain it, often the customer is testing, not refusing. If you do move, get something back, a bigger order, faster payment, a longer commitment, a referral. A concession for a concession. Put an expiry on every discount, so a one-off can't quietly become the price.

Some discounts are sound business: clearing genuinely dead stock, a volume deal where the extra units really do cover the gap, a costed move to win a strategic customer. The difference between those and the rest isn't the size of the discount. It's that someone did the arithmetic first. Discount on purpose, never on reflex.

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Moor & Co helps small business owners hold their prices with confidence and discount only when the maths genuinely works. The tools behind it run on [3DMAI](https://www.3dmai.co.uk), whose Pricing & Scenario Modeller shows exactly what a discount does to your profit, and how much more you'd need to sell to cover it, before you offer it. [Book a free 30-minute conversation](https://moorandco.co.uk), no commitment, or download the full briefing, The Discount Trap.