Discount calculator
Sale price, savings and stacked discounts — plus what the original price was.
Stacked on the reduced price
Discount reference
| Original | 10% off | 20% off | 25% off | 30% off | 40% off | 50% off | 70% off |
|---|---|---|---|---|---|---|---|
| $20.00 | $18.00 | $16.00 | $15.00 | $14.00 | $12.00 | $10.00 | $6.00 |
| $50.00 | $45.00 | $40.00 | $37.50 | $35.00 | $30.00 | $25.00 | $15.00 |
| $100.00 | $90.00 | $80.00 | $75.00 | $70.00 | $60.00 | $50.00 | $30.00 |
| $200.00 | $180.00 | $160.00 | $150.00 | $140.00 | $120.00 | $100.00 | $60.00 |
| $500.00 | $450.00 | $400.00 | $375.00 | $350.00 | $300.00 | $250.00 | $150.00 |
How it works
A discount multiplies the price by (1 − rate). Stacked discounts multiply again — they do not add.
final = price × (1 − d₁) × (1 − d₂) “30% off, then an extra 20%” is 44% off, not 50%
0.7 × 0.8 = 0.56, so you pay 56% of the original. The second discount applies to a smaller number, so it delivers less than its headline. This is the most common piece of retail arithmetic people get wrong, and stores know it.
Discount then tax, or tax then discount?
It makes no difference — multiplication is commutative. Retailers apply the discount first because tax is legally owed on the amount actually paid, but the total is identical either way.
Reverse mode
To recover an original price, divide rather than multiply. A £70 item marked “30% off” was £100 — not £91, which is what adding 30% back would wrongly give you. Dividing by 0.7 is the correct operation.