Discount calculator

How to use the discount calculator

1. Choose "Price and % off" or "Original and sale price".
2. Type the original price and either the discount percentage or the sale price.
3. Read the sale price and saving, or the percentage off.

How to work out a discount

Sale price = original price x (1 - discount as a decimal). 30% off £85 is £85 x 0.7 = £59.50, a saving of £25.50. 15% off a £1,299 sofa is £1,299 x 0.85 = £1,104.15, saving £194.85.

To check a shop's claim, go the other way: saving / original price x 100. A coat reduced from £120 to £90 is £30 off, and 30 / 120 x 100 = 25% off.

Why two discounts do not add up

An extra 10% off a price already cut by 20% is not 30% off. The second discount is taken from the reduced price.

On £100: 20% off gives £80. Then 10% off £80 is £8, leaving £72. That is 28% off in total, not 30%. The bigger the discounts, the wider the gap: 50% off then another 50% off leaves you paying 25%, which is 75% off, not 100%.

The order makes no difference. 10% then 20% also ends at £72.

Reading sale labels

• "Up to 50% off" means at least one item is half price. Many will be reduced by less.
• "Save £40" on a £200 item is 20% off. Put both figures in the calculator to compare offers quoted in different ways.
• "Buy one get one half price" is 25% off per item when both cost the same, because you pay 1.5 prices for 2.
• "3 for 2" is a third off each item when all three cost the same.

A discount is only a saving if you would have bought the item anyway.

Questions people ask