Discount Calculator
Calculate the sale price after a discount, or find the discount percentage between original and sale prices. See also Markup Calculator and Percentage Calculator.
How to Calculate Discounts
To calculate a discount, multiply the original price by the discount percentage (as a decimal) to get the discount amount, then subtract it from the original price to get the sale price. For example, a 25% discount on a $200 item: $200 × 0.25 = $50 discount, so the sale price is $200 − $50 = $150. To find the discount percentage when you know both prices, divide the difference by the original price and multiply by 100.
Discount Formula
Discount Amount = Original Price × (Discount% / 100)
Sale Price = Original Price − Discount Amount
To find discount percentage:
Discount% = ((Original − Sale) / Original) × 100
Shortcut:
Sale Price = Original × (1 − Discount% / 100)
Example Calculation
Original Price: $200.00
Discount: 25%
Discount Amount = $200 × 0.25 = $50.00
Sale Price = $200 − $50 = $150.00
You save: $50.00
Discount Reference Table
| Original | 10% Off | 20% Off | 25% Off | 30% Off | 50% Off |
|---|---|---|---|---|---|
| $25 | $22.50 | $20.00 | $18.75 | $17.50 | $12.50 |
| $50 | $45.00 | $40.00 | $37.50 | $35.00 | $25.00 |
| $100 | $90.00 | $80.00 | $75.00 | $70.00 | $50.00 |
| $200 | $180.00 | $160.00 | $150.00 | $140.00 | $100.00 |
| $500 | $450.00 | $400.00 | $375.00 | $350.00 | $250.00 |
| $1,000 | $900.00 | $800.00 | $750.00 | $700.00 | $500.00 |
Frequently Asked Questions
How do I calculate a double discount?
For stacked discounts (e.g., 20% off then an additional 10% off), apply them sequentially. A $100 item at 20% off = $80, then 10% off $80 = $72. This is NOT the same as 30% off ($70). Stacked discounts always result in a smaller total discount than adding the percentages.
Is "buy one get one 50% off" the same as 25% off?
Yes, if you buy exactly two items at the same price. BOGO 50% off means you pay 150% for two items instead of 200%, which is a 25% discount on the total. However, if items have different prices, the actual discount varies.
How do I calculate the original price from a sale price?
Divide the sale price by (1 − discount/100). For example, if the sale price is $75 after a 25% discount: $75 / (1 − 0.25) = $75 / 0.75 = $100 original price.
Does this include sales tax?
No. This calculator shows the price after discount but before tax. In most jurisdictions, sales tax is applied to the discounted price, not the original price. Use a sales tax calculator to determine the final amount with tax.
Solved Examples
Example 1: Black Friday sale on electronics
Solution:
Original price = $899, Discount = 25%
Discount amount = $899 × 0.25 = $224.75
Sale price = $899 - $224.75 = $674.25
Answer: You save $224.75 and pay $674.25 for the item.
Example 2: Stacked discounts (coupon + sale)
Solution:
Original price = $200, Store sale = 30% off, Extra coupon = 15% off
After 30% off: $200 × 0.70 = $140
After additional 15% off: $140 × 0.85 = $119
Total savings = $200 - $119 = $81 (effective 40.5% off, NOT 45%)
Answer: Final price = $119 (40.5% total discount — stacked discounts don't simply add up).
Example 3: Finding original price from sale price
Solution:
Sale price = $67.50, Discount = 25%
Original Price = Sale Price / (1 - Discount%)
Original Price = $67.50 / (1 - 0.25) = $67.50 / 0.75 = $90.00
Answer: The original price was $90.00 before the 25% discount.
Practice Questions
Try these on your own:
- A $1,200 laptop is 20% off. What is the sale price? (Answer: $960)
- You pay $42 for a shirt originally priced at $60. What discount percentage did you receive? (Answer: 30%)
- A store offers "Buy 2, get 1 free" on $30 items. What is the effective per-item discount? (Answer: 33.3% off per item = $20 each)
- A $500 item is 40% off, then an extra 10% coupon applies. What do you pay? (Answer: $270)
- You want to pay no more than $150. The item is 35% off. What is the maximum original price you can buy? (Answer: $230.77)
Common Mistakes to Avoid
The biggest misconception is that stacked discounts add up linearly. A 30% off + 20% off is NOT 50% off — it's actually 44% off total (1 - 0.70 × 0.80 = 0.44). Another common error is confusing "% off" with "% of." If something is 25% off, you pay 75% of the original price. People also forget to factor in sales tax AFTER the discount — the tax applies to the discounted price, not the original. A frequent mistake in business is discounting too deeply without understanding the impact on margins: a 20% discount requires 25% more units sold just to maintain the same profit (at 50% margin). Finally, many shoppers are misled by inflated "original" prices that make discounts appear larger than the actual value saved.
Key Takeaways
- Sale Price = Original Price × (1 - Discount%), or equivalently: Original - (Original × Discount%).
- Stacked discounts multiply, not add: 30% + 20% off = 44% total, not 50%.
- To find the original price: Original = Sale Price / (1 - Discount%).
- A business needs to sell proportionally more units to offset each % discount on profit margins.
- Always calculate the actual dollar savings rather than relying on the percentage to assess deal value.
- Sales tax applies to the discounted price, reducing the effective tax you pay.