How to use the discount calculator
- Type the original price.
- Tap a discount or type your own percentage.
- If the shop offers an extra % off the sale price, enter it as the extra discount.
The formula
Sale price = Price × (1 − discount ÷ 100)
You save = Price − Sale price
Worked examples
25% off $80
$80 × 0.75 = $60. You save $20.
Stacked discounts are not added together
“25% off, plus an extra 10% at the checkout” sounds like 35% off – but the second discount is taken from the already reduced price. $80 × 0.75 × 0.90 = $54, a total discount of 32.5%, not 35%. The calculator shows this total for you.
Finding the original price
If an item costs $45 after 25% off, divide by 0.75: $45 ÷ 0.75 = $60 was the original price.
Smart shopping tips
- “Buy one, get one half price” is the same as 25% off when you buy two items of the same price.
- In the US, sales tax is added after the discount, so the price at the till will be higher than the sale price shown on the tag.
- Compare the sale price with other shops – a big percentage off an inflated “original” price is not always a good deal.
Frequently asked questions
How do I calculate 30% off?
Multiply the price by 0.7. For example $120 × 0.7 = $84, so you save $36.
Is 20% off and then 20% off the same as 40% off?
No. Two 20% discounts give 1 − 0.8 × 0.8 = 36% off in total, because the second discount is applied to the lower price.
How do I work out the percentage discount from two prices?
Divide the saving by the original price and multiply by 100. From $50 down to $35: $15 ÷ $50 × 100 = 30% off.
Last reviewed: November 13, 2026
Results are estimates for general information only and are not financial, tax, medical or legal advice. Check important figures with a qualified professional.