How to use the discount calculator
Enter the original price and the percentage off, and the sale price and your savings appear instantly. If a store is running a second promotion — say an extra 10% at the checkout — add it in the second field to see the real final price and the true effective discount.
The trap with stacked discounts
Retailers often advertise offers like “30% off, plus an extra 10% today only.” It is natural to add those together and expect 40% off, but discounts applied in sequence multiply instead. The second discount only ever applies to what is left after the first, so the combined saving is always a little less than the sum. This calculator shows the genuine effective percentage so you know exactly what you are paying.
Working backwards
The same maths lets you check whether a “sale” price is really a bargain. If you know the final price and the advertised discount, divide the sale price by one minus the discount to recover the original — useful for spotting inflated “was” prices. Every figure here is computed in your browser and nothing you type is stored.