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Discount Calculator

Work out the final price of any product after applying a discount and see exactly how much you save.

Any discount Live result Works out your saving

Discount details

£
Discount percentage
%

Final price

£80.00
With 20% off
Original price£100.00
Discount-£20.00
Final price£80.00
What you pay vs what you save
80%
20%
What you pay Your saving

How discounts work

Learn how to work out discounts and spot the genuinely good deals

Percentage discount

Most common

The most common type of discount. A percentage is taken off the original price.

Formula
Final price = Original price × (1 - Discount/100)
Example: £100 - 20% = 100 × 0.80 = £80

BOGOF and 3-for-2 deals

Multibuys

Offers that mean buying several units. Buy one get one free (BOGOF) works out at a 50% discount per unit.

Equivalents
BOGOF = 50% off | 3 for 2 = 33.3% off

Second item at X%

Watch out

Be careful with these offers. "Second item half price" is only a 25% real discount across the whole purchase.

Example
2 items at £10, 2nd at 50% = £15 total (25% real)

Stacked discounts

Common mistake

20% plus an extra 10% is NOT 30%. The discounts are applied one after the other, they are not added together.

Real calculation
100 × 0.80 × 0.90 = £72 (28% real, not 30%)

Frequently asked questions about discounts

We answer the most common questions about offers and sales

Multiply the price by 0.80 (which is 1 - 0.20). For example: £50 with 20% off = 50 × 0.80 = £40. Quick tip: a 20% discount means paying 80%.
They are equivalent in terms of saving per unit. But buy one get one free forces you to buy 2 items, whereas 50% off you can use on a single item. If you only need one, 50% off is the better deal.
They are multiplied, not added. Example: 20% plus an extra 10% = 100 × 0.80 × 0.90 = £72. The total discount is 28%, not 30%. General formula: (1-d1) × (1-d2).
Check the price history with tools such as CamelCamelCamel or Keepa. Retailers sometimes inflate prices before the sales. Compare with other shops as well. In the UK, the Price Marking Order requires the lowest price from the previous 30 days to be shown, which is a useful reference.
It means that SOME products have 50% off, but most will have smaller discounts. It is a marketing hook. Always check the actual discount on each individual product.
It depends on the product. Clothing and electronics usually have good discounts in the sales. But if it is something you need urgently, the potential saving may not be worth the wait.

How to work out discounts: the complete guide

Knowing how to work out discounts correctly is essential for making smart buying decisions and not falling for fake offers. This calculator tells you the final price of any product after applying a percentage discount, clearly showing how much money you save and what percentage of the original price you are actually going to pay.

The formula for working out a discount is simple: multiply the original price by the discount percentage (as a decimal) to get the saving, or simply multiply by (1 - discount) to get the final price. This calculator does the whole thing for you.

Quick discount multiplier table

Memorise these multipliers to work out discounts in your head without a calculator:

Discount You pay Multiply by £100 becomes
5% 95% × 0.95 £95
10% 90% × 0.90 £90
15% 85% × 0.85 £85
20% 80% × 0.80 £80
25% 75% × 0.75 £75
30% 70% × 0.70 £70
40% 60% × 0.60 £60
50% 50% × 0.50 £50
70% 30% × 0.30 £30

Watch out: how stacked discounts work

When you are told "20% plus an extra 10%", the real discount is NOT 30%. The discounts are applied one on top of the other:

Original price

£100

After -20%

£80

After a further -10%

£72

Real discount

28%

Formula: Final price = Original × (1-d1) × (1-d2) = 100 × 0.80 × 0.90 = £72

Sales and offers calendar in the UK 2026

Plan your shopping by knowing the sale dates when you will find the best discounts:

Event Date Discounts Best for
Boxing Day & January sales 26 Dec - Jan 30-70% Clothing, footwear, fashion
Summer sales Jun - Aug 30-70% Clothing, footwear, fashion
Amazon Prime Day July (2 days) 15-40% Electronics, Amazon devices
Singles' Day (11.11) 11 November 20-50% AliExpress, online marketplaces
Black Friday Last Fri Nov 20-50% Electronics, all kinds
Cyber Monday Mon after BF 20-40% Online, technology

5 tips to avoid falling for fake offers

1

Check the price history

Use tools such as Keepa or CamelCamelCamel for Amazon, or PriceRunner and Idealo to compare. Many retailers inflate prices before the sales.

2

Work out the price per unit

On BOGOF or multibuy offers, divide the total price by the number of units. Sometimes the "offer" pack is dearer than buying the items separately.

3

Be wary of huge discounts

80% off branded products is suspicious. The original price was probably inflated artificially.

4

Compare across several shops

One shop's "sale" price may be another's everyday price. Never buy without comparing at least 2-3 options.

5

Ask yourself whether you really need it

The biggest saving is not buying what you do not need. 70% off is still spending money on something unnecessary.

Tip: In the winter and summer sales, discounts usually deepen from the second week onwards. If you can wait, you will find better prices (though with less choice of sizes and styles).

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