Discount calculator
Enter the original price and the discount, and see what you pay and what you save.
Result
- You pay
- $90.00
- You save
- $30.00
- As a fraction of the original
- 75.00%
Worked examples
A single discount
A $120 coat is reduced by 25%.
- 120 × 0.25 = 30
- 120 − 30 = 90
You pay $90 and save $30.
Stacked discounts
30% off, then a further 20% off at the till.
- 0.70 × 0.80 = 0.56
- 1 − 0.56 = 0.44
44% off in total, not 50%.
Discounts stack multiplicatively
Two discounts applied one after the other do not add. Taking 30% off and then 20% off leaves 70% × 80% = 56% of the original price, which is a 44% discount — noticeably less than the 50% the two figures suggest.
The second discount applies to the already-reduced price, so it is worth less in absolute terms than the first. Retailers rely on this: "extra 20% off sale items" reads larger than it is.
Discount before or after tax
Where sales tax or VAT applies, the discount is normally taken first and tax calculated on the reduced amount. The order matters to the final figure, and it is worth checking which convention a seller uses if the sum is large.
Formula
final = price × (1 − discount ÷ 100)
What stacked discounts actually come to
Two discounts never add. The second applies to the already-reduced price, so the combined figure is always less than the sum.
| First | Second | Sounds like | Actually is |
|---|---|---|---|
| 10% | 10% | 20% | 19% |
| 20% | 10% | 30% | 28% |
| 30% | 20% | 50% | 44% |
| 50% | 20% | 70% | 60% |
| 50% | 50% | 100% | 75% |
| 40% | 25% | 65% | 55% |
Common discounts on round prices
| Original | 10% off | 25% off | 33% off | 50% off |
|---|---|---|---|---|
| $20 | $18.00 | $15.00 | $13.40 | $10.00 |
| $50 | $45.00 | $37.50 | $33.50 | $25.00 |
| $80 | $72.00 | $60.00 | $53.60 | $40.00 |
| $120 | $108.00 | $90.00 | $80.40 | $60.00 |
| $250 | $225.00 | $187.50 | $167.50 | $125.00 |
Frequently asked questions
How do I calculate a discount?
Multiply the price by the discount percentage divided by 100 to get the saving, then subtract it. For 25% off $120: 120 × 0.25 = $30 saved, leaving $90.
How do I add two discounts together?
You multiply what remains rather than adding the discounts. 30% off then 20% off leaves 0.7 × 0.8 = 0.56 of the price, a 44% total discount.
What is the quickest way to take a percentage off in my head?
Work with 10% and 5% blocks. 10% of $80 is $8, so 30% is $24 and 35% is $28. Subtracting from the original is usually faster than computing the remainder directly.
Which order should discounts and tax be applied in?
Discount first, then tax on the reduced amount. That is the standard convention and produces a lower total than taxing first.
What does BOGO work out to as a percentage?
Buy one get one free is 50% off when you buy two. Buy one get one half price is 25% off across the pair.
How do I calculate the original price from a discount?
Divide the sale price by one minus the discount. A $90 item at 25% off was 90 ÷ 0.75 = $120.
Is 50% off then 50% off the same as free?
No — it is 75% off. The second discount applies to the already-halved price, leaving a quarter of the original.
How much do I save with an extra 20% off a 30% sale?
44% of the original price, not 50%. You pay 0.7 × 0.8 = 0.56 of the ticket price.