About this calculator
Enter your current price, your cost per sale and the percentage increase you're considering. The calculator shows how much of your sales you could lose before you're worse off.
The answer surprises most people: with a healthy margin, even a small price rise lets you lose a good number of customers and still make the same profit.
Worked examples
Real numbers, worked out by the same calculator. Press “Use these numbers” to try one above.
£10 price, £6 cost, +10%
- Sales you can lose before you're worse off
- 20%
- New price
- £11.00
- Profit per sale now
- £4.00
- Profit per sale after the rise
- £5.00
- Sales now
- 1,000
- Sales needed after the rise
- 800
- Profit now
- £4,000.00
Raising the price from £10.00 to £11.00 (10%) means you can lose up to 20% of your sales and still make the same total profit.
Show the working
- Profit per sale now = £10.00 − £6.00 = £4.00.
- The increase adds £1.00 to every sale, so profit per sale becomes £5.00.
- Break-even: you can lose a share of sales equal to the increase ÷ the new profit per sale = £1.00 ÷ £5.00 = 20%.
- Lose more sales than that and you earn less than you do today; lose fewer and you earn more.
£50 price, £40 cost, +5%
- Sales you can lose before you're worse off
- 20%
- New price
- £52.50
- Profit per sale now
- £10.00
- Profit per sale after the rise
- £12.50
Raising the price from £50.00 to £52.50 (5%) means you can lose up to 20% of your sales and still make the same total profit.
Show the working
- Profit per sale now = £50.00 − £40.00 = £10.00.
- The increase adds £2.50 to every sale, so profit per sale becomes £12.50.
- Break-even: you can lose a share of sales equal to the increase ÷ the new profit per sale = £2.50 ÷ £12.50 = 20%.
- Lose more sales than that and you earn less than you do today; lose fewer and you earn more.
£100 price, £30 cost, +20%
- Sales you can lose before you're worse off
- 22.22%
- New price
- £120.00
- Profit per sale now
- £70.00
- Profit per sale after the rise
- £90.00
- Sales now
- 200
- Sales needed after the rise
- 156
- Profit now
- £14,000.00
Raising the price from £100.00 to £120.00 (20%) means you can lose up to 22.22% of your sales and still make the same total profit.
Show the working
- Profit per sale now = £100.00 − £30.00 = £70.00.
- The increase adds £20.00 to every sale, so profit per sale becomes £90.00.
- Break-even: you can lose a share of sales equal to the increase ÷ the new profit per sale = £20.00 ÷ £90.00 = 22.22%.
- Lose more sales than that and you earn less than you do today; lose fewer and you earn more.
The break-even rule
A price rise adds the same extra amount to every sale you keep. You can afford to lose sales until the profit from those extra pounds exactly replaces the profit from the lost sales. The share you can lose is increase ÷ new profit per sale. With a £10 price, £6 cost and a 10% rise (£1), the new profit per sale is £5, so you can lose £1 ÷ £5 = 20% of your sales.
Why margin matters
The lower your margin, the more a price rise helps. If you keep £1 of every £100 sale, a 5% rise (£5) means you could lose five-sixths of your sales and break even. If your margin is high, there is less to gain from a rise, although you can still afford to lose some customers.
What this does not tell you
It shows the break-even point, not what will happen. Some customers will leave, some won't notice, and a rise can change how your product is seen. Use the result to judge how risky a rise is, not to predict the outcome.
Frequently asked questions
How many customers can I lose if I raise my price 10%?
It depends on your margin. With a 40% margin, a 10% rise breaks even if you lose up to 20% of sales.
Does this include fixed costs?
No. Fixed costs are the same whether you sell more or less, so only the profit per sale matters for this question.
What if my cost is higher than my price?
Then you lose money on every sale and a price rise should come first. The calculator says so.
Is a price rise always a good idea?
Not always. If you'd lose more sales than the break-even share, you'd be worse off.
Formulas tested against hand-worked answers. Last reviewed 29 September 2026. These calculators do arithmetic only; they are not financial, tax or legal advice.