Discount Calculator
Percentage discounts are one of the most common calculations in retail, sales, and negotiations. Whether you are offering a promotional markdown, calculating the cost of a trade discount, figuring out what a sale price really means, or checking how much you actually save from an advertised deal, this calculator gives you the exact discount amount and final price in seconds.
Enter the original price and the discount percentage. The calculator shows the amount you save in currency terms and the final price you pay or charge. For example, a 25% discount on a £200 item removes £50, leaving a final price of £150. You can also reverse the calculation: if you know the sale price and the discount rate, divide the sale price by (1 − discount rate) to find the original price before the reduction.
An important caution applies when stacking multiple discounts: they are not additive. A 20% discount followed by a 10% discount on a £100 item gives £72, not £70 — because the second discount applies to the already-reduced price of £80, not the original £100. This distinction matters in negotiations, promotions, and supply chain contracts. For a deeper analysis of how discounts erode your profit margins, see the Discount Impact on Margin guide.
Formula
Discount Amount = Original Price × (Discount % ÷ 100) Final Price = Original Price − Discount Amount
Multiply the original price by the discount rate to find the savings amount. Subtract that from the original price to get the final price you pay.
Worked Examples
Frequently Asked Questions
How do I calculate a percentage discount?▾
Multiply the original price by the discount percentage divided by 100. For 30% off £80: £80 × 0.30 = £24 discount. Final price = £80 − £24 = £56. Equivalently, multiply the original price by (1 − discount rate): £80 × 0.70 = £56.
Do multiple discounts stack?▾
Successive discounts are applied one after another, not added together. A 20% discount followed by a 10% discount on £100 gives £72 — not £70. Each discount applies to the reduced price from the previous step: 20% off £100 = £80, then 10% off £80 = £72. Always calculate sequentially rather than adding the percentages.
How do I find the original price from a discounted price?▾
Divide the final price by (1 − discount rate as a decimal). If you paid £75 after a 25% discount: £75 ÷ 0.75 = £100 original price. This works because the discounted price represents 75% of the original, so dividing by 0.75 reverses the reduction.
What is 20 percent off a price?▾
To find 20% off, multiply the original price by 0.20 to get the discount amount, then subtract. For example, 20% off £80 = £80 × 0.20 = £16 discount. Final price = £80 − £16 = £64. Alternatively, multiply directly by 0.80: £80 × 0.80 = £64.
How much does a discount actually cost my profit margin?▾
Discounts damage profit margin disproportionately to their size. With a 40% gross margin, a 20% price discount reduces your margin from 40% to 25% — and you need approximately 100% more unit sales to recover the same total profit. The lower your margin, the more damaging any given discount percentage is. For a complete analysis, see the Discount Impact on Margin guide.
How do I calculate the percentage discount from original and sale price?▾
Subtract the sale price from the original price to get the discount amount, then divide by the original price and multiply by 100. For example, if an item originally costs £80 and is now £60: discount = (£80 − £60) ÷ £80 × 100 = 25%. This tells you what percentage was taken off the original price.
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All calculations are for informational purposes only. They should not replace professional financial, tax, or legal advice. Always consult a qualified professional for decisions affecting your finances or business.