How to calculate a discount
| You want | Formula | Example |
|---|---|---|
| Sale price | price × (1 − discount ÷ 100) | $80 × 0.75 = $60 |
| Savings | price × discount ÷ 100 | $80 × 0.25 = $20 |
| Percent off | (old − new) ÷ old × 100 | ($129.99 − $89.99) ÷ $129.99 = 30.8 % |
| Original price | sale price ÷ (1 − discount ÷ 100) | $60 ÷ 0.75 = $80 |
Stacked discounts are not added up
“20 % off plus an extra 10 % at checkout” is not 30 % off. The second discount comes off the already reduced price: $100 − 20 % = $80, then − 10 % = $72. That is 28 % off in total. The “Double discount” mode does this for you.
Quick table: price after discount
| Price | 10 % off | 20 % off | 25 % off | 30 % off | 50 % off | 70 % off |
|---|---|---|---|---|---|---|
| $20 | 18.00 | 16.00 | 15.00 | 14.00 | 10.00 | 6.00 |
| $50 | 45.00 | 40.00 | 37.50 | 35.00 | 25.00 | 15.00 |
| $100 | 90.00 | 80.00 | 75.00 | 70.00 | 50.00 | 30.00 |
| $250 | 225.00 | 200.00 | 187.50 | 175.00 | 125.00 | 75.00 |
| $500 | 450.00 | 400.00 | 375.00 | 350.00 | 250.00 | 150.00 |
Black Friday shopping tips
- Black Friday 2026 is on November 27, Cyber Monday on November 30. Many stores start their deals a week earlier.
- Check the “was” price: a discount is only as good as the price it is taken from. Price history tools help you spot inflated reference prices.
- Add sales tax and shipping: in the US, sales tax is added at checkout, so the final price is higher than the tag.
- Percent or dollars? “$20 off $100” is 20 % off, but only 13.3 % off a $150 order.
For other percentage problems use the percentage calculator.
Frequently asked questions
How do I calculate 20 % off?
Multiply the price by 0.8. A $79.99 item costs $63.99, and you save $16.
What percent off is $50 down to $35?
($50 − $35) ÷ $50 × 100 = 30 % off.
Are two 10 % discounts the same as 20 %?
No, they make 19 %: $100 → $90 → $81. Stacked discounts always add up to a little less than their sum.
Is the discount applied before or after tax?
In the US the discount usually comes off the pre-tax price, and tax is calculated on the reduced amount. The percentage saved is the same either way.