Discount Calculator
Shops present discounts in whatever form flatters them: percentages off, buy-one-get-one, stacked coupons, or a strikethrough price nobody ever paid. This calculator gives you the final price and the actual amount saved, and the notes below show how to compare offers that are deliberately hard to compare.
Inputs
Result
2,249.25
You save 749.75
How the discount calculator works
Sale price = original × (1 − discount). Amount saved = original × discount.
Stacked discounts multiply, they do not add: 20% then 10% off gives 0.8 × 0.9 = 0.72, a 28% total reduction, not 30%.
To find the discount from two prices: discount = (original − sale) ÷ original × 100.
Worked example: comparing three offers on a 4,000 item
- 30% off: 4,000 × 0.7 = 2,800. Saved 1,200.
- 20% off plus an extra 10% at checkout: 4,000 × 0.8 × 0.9 = 2,880. Saved 1,120.
- Buy two get one free on three items: 12,000 becomes 8,000, an effective 33.3% off — but only if you need three.
- Per-unit cost: 2,800 versus 2,880 versus 2,667.
- The headline 30% offer beats the stacked 'up to 30%' offer by 80.
Common mistakes to avoid
Adding stacked percentages
Sequential discounts always total less than their sum. The second is applied to an already reduced price.
Judging value against an inflated list price
A 60% discount from a price never charged is a marketing device. Compare against the typical street price instead.
Counting the whole discount as savings on bulk deals
Buying three to save on one is only a saving if you would have bought three anyway.
Frequently asked questions
How do I calculate 20% off?
Multiply the price by 0.8. For 20% off 1,750: 1,750 × 0.8 = 1,400.
Is a 20% + 10% discount the same as 30%?
No. Stacked, it works out to 28% off. The order does not matter; the total is always less than the sum.
Is tax applied before or after the discount?
Almost always after, on the reduced price — so a discount also reduces the tax you pay.
How do I find the original price from a sale price?
Divide by (1 − discount). A 2,800 item at 30% off was originally 2,800 ÷ 0.7 = 4,000.
What discount does buy-one-get-one-free equal?
50% off, provided you take both units. Buy-two-get-one is 33.3% across three units.
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