Discount and sale price calculator
To find a sale price, multiply the original price by 1 minus the discount rate. A $80 item that is 30% off costs 80 × 0.70 = $56. Two discounts do not simply add: 20% off followed by an extra 10% off is 28% off in total, not 30%. Choose a mode and enter your numbers.
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Arithmetic estimate only. Prices at checkout may be rounded and sales tax is not included.
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Discount formulas
\[ \text{sale price} = \text{original price} \times \left( 1 - \dfrac{\text{discount}}{100} \right) \]
\[ \text{original price} = \dfrac{\text{sale price}}{1 - \dfrac{\text{discount}}{100}} \]
\[ \text{percent off} = \dfrac{\text{original} - \text{sale}}{\text{original}} \times 100 \]
For a price increase, use 1 plus the percentage: +15% means multiply by 1.15.
Stacked discounts: why 20% + 10% is not 30%
The second discount applies to the price that is already reduced, so you multiply the multipliers:
\[ \text{final multiplier} = (1 - d_{1}) \times (1 - d_{2}) \times (1 - d_{3}) \]
| Discounts | Real total discount |
|---|---|
| \( 10\% + 10\% \) | 19% |
| \( 20\% + 20\% \) | 36% |
| \( 30\% + 20\% \) | 44% |
| \( 50\% + 20\% \) | 60% |
Add sales tax after the discount: the tax is figured on the reduced price in most states, though a few apply it differently to coupons.
3 real-life examples
A $129.99 jacket at 35% off
\( 129.99 \times 0.65 = \) $84.49. You save $45.50.
40% off plus an extra 15% coupon
On $100: \( 100 \times 0.60 \times 0.85 = \) $51. The real discount is 49%, not 55%.
What was the price before 25% off?
A sale item costs $42 after 25% off. Original price = 42 ÷ 0.75 = $56.