Discount Calculator
Enter the original price and the discount to see what you actually pay — including a second discount if the sale stacks one on top of another.
- You save
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- Effective discount
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- Before tax
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Enter a price and a discount.
Working out a sale price
To find a sale price, multiply the original by (100 − discount) ÷ 100. A $80 jacket at 25% off costs 80 × 0.75 = $60, saving $20. The quickest mental route is to find 10% by moving the decimal one place left, then build from there: 10% of $80 is $8, so 25% is $8 + $8 + $4 = $20 off. Note that stacked discounts multiply rather than add — 20% off followed by another 20% off is 36% off in total, not 40%.
Why "20% off plus an extra 20%" is not 40% off
Stacked discounts apply one after another, each to a smaller number, so they never add up to the sum of their parts.
On a $100 item: the first 20% takes it to $80, and the second 20% comes off the $80, removing $16 rather than $20. You pay $64 — a 36% discount, not 40%.
| Stacked offer | Sounds like | Actually is |
|---|---|---|
| 20% + 20% | 40% off | 36% off |
| 30% + 20% | 50% off | 44% off |
| 50% + 20% | 70% off | 60% off |
| 50% + 50% | 100% off | 75% off |
The general rule: the combined discount is 1 − (1 − d₁)(1 − d₂).
Working backwards from the sale price
If you know the sale price and the discount but not the original, divide rather than multiply.
A jacket is $60 after 25% off. The $60 represents 75% of the original, so the original is 60 ÷ 0.75 = $80. Adding 25% to $60 would wrongly give $75.
The same logic strips tax: a $108 total including 8% tax has a pre-tax price of 108 ÷ 1.08 = $100.
What common offers are really worth
| Offer | Effective discount |
|---|---|
| Buy one get one free (BOGO) | 50% off, if you want both |
| Buy one get one half price | 25% off across the two |
| Buy 2 get 1 free (3 for 2) | 33.3% off |
| "Half price" then 20% off | 60% off |
| Tax-free day at 8% tax | 7.4% off the total |
Multi-buy offers are only genuine savings when you would have bought the extra item anyway.
How to use the Discount Calculator
- Enter the original price on the tag.
- Enter the advertised percentage off.
- If a coupon takes a further percentage off at checkout, enter it in the second discount field.
- Add your local sales tax if you want the true till total.
Frequently asked questions
How do I calculate 25% off?
Multiply the price by 0.75. For $80: 80 × 0.75 = $60. Or find a quarter of the price and subtract it — a quarter of $80 is $20, leaving $60.
How do I find the original price from a sale price?
Divide the sale price by (100 − discount) ÷ 100. A $60 item after 25% off was 60 ÷ 0.75 = $80 originally.
Do two discounts add together?
No. They apply in sequence, each to the reduced price. 20% then 20% gives 36% off overall. Use the second discount field above to get the exact figure.
Is tax charged before or after the discount?
After. Sales tax is calculated on what you actually pay, so a discount reduces the tax too. This calculator applies tax to the discounted price.
What is a 30% discount on $50?
$15 off, leaving $35. Ten percent of $50 is $5, so 30% is $15.
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Last reviewed September 4, 2026. Results are estimates for general information only.