Work out any discount in seconds
"25% off" sounds simple until you are standing in a shop trying to work out the actual price in your head. This free discount calculator removes the mental arithmetic: enter the original price and discount percentage to see the sale price and exactly how much you save, or enter the original and sale price to find out what discount was really applied.
The simple formula behind every markdown
A discount is just a percentage reduction applied to a starting price. Converting the discount to a decimal (25% becomes 0.25) and subtracting it from 1 gives the fraction of the original price you actually pay — 0.75, or 75%, in this example. Multiply that fraction by the original price and you have the sale price; subtract the sale price from the original to see the amount saved.
Why percentages off are not always what they seem
Retailers frequently advertise stacked discounts — "30% off, plus an extra 10% at checkout" — and it is natural to assume that adds up to 40% off. It does not. The second discount applies to the already-reduced price, not the original, so the combined effect is always slightly less than simply adding the two percentages. A $100 item at 30% off becomes $70; a further 10% off that $70 brings it to $63 — an overall discount of 37%, not 40%. Knowing this prevents overestimating how good a "stacked" deal actually is.
Working backwards: finding the real discount rate
Sometimes a sale price is advertised without a clear percentage, or you want to check a store's maths. Entering both the original and the sale price reverses the formula to reveal the exact discount rate applied — handy for comparing which of several "deals" is genuinely the better one.
Where this calculator helps
- Shopping — quickly checking whether a sale price matches the advertised percentage.
- Budgeting — working out real costs before committing to a purchase.
- Comparing deals — finding the true discount rate behind a promotional price.
How to use it
Enter the original price and either a discount percentage or the sale price, and the missing figures — sale price, amount saved, or effective discount rate — fill in instantly as you type.
A worked example with stacked discounts
Suppose a $150 jacket is 20% off, with an extra 15% off at checkout for signing up to a newsletter. The first discount brings it to $150 × 0.80 = $120. The second discount then applies to that $120, not the original $150: $120 × 0.85 = $102. The final price is $102, which is a genuine overall discount of about 32% — noticeably less than the 35% a shopper might assume from simply adding 20% and 15%. Running both steps through the calculator in sequence — or checking the final numbers against the original price — makes the true savings on any stacked promotion obvious in seconds.
Frequently asked questions
What formula does the calculator use?
Sale price equals the original price multiplied by (1 minus the discount as a decimal) — for example, a $80 item at 25% off is 80 × 0.75 = $60.
Can I work backwards from the sale price?
Yes. Enter the original price and the final sale price, and the calculator works out exactly what percentage discount was applied.
How do two stacked discounts combine — do they just add up?
No, and this catches many shoppers out. Two discounts apply one after the other to a shrinking price, so 20% off followed by a further 10% off is not 30% off overall — it works out closer to 28%.
Does this calculator include sales tax?
No, it calculates the discounted price only. Tax rates vary by location and are usually applied after any discount, so add tax separately based on your local rate.