How to Calculate a Discount
Learn how to calculate percent off, the amount saved, and the final sale price. This guide also explains stacked discounts and how to work backward to an original price.
Quick answer
Convert the discount percentage to a decimal, multiply it by the original price to find savings, then subtract the savings from the original price.
Discount amount = Original price × (Discount % ÷ 100) Sale price = Original price − Discount amountWhat is a discount?
A discount reduces an original or list price. It can be stated as a percentage, such as 20% off, or as a fixed amount, such as $15 off.
A percentage discount is calculated from the original price. For example, 20% off a $100 item saves $20 and produces a sale price of $80.
Discount formulas
For a percentage discount, convert the percent to decimal form before multiplying. For example, 25% becomes 0.25.
How to calculate a discount
- Start with the original price.
- Convert the discount percentage to a decimal by dividing by 100.
- Multiply the original price by that decimal to find the discount amount.
- Subtract the discount amount from the original price.
Example: Calculate 25% off $120
- Convert 25% to a decimal: 25 ÷ 100 = 0.25
- Find the discount: $120 × 0.25 = $30
- Subtract the discount: $120 − $30 = $90
Answer: You save $30, and the sale price is $90.
Discount examples
Example: What is 20% off $80?
- Convert 20% to a decimal: 0.20
- Find savings: $80 × 0.20 = $16
- Find the sale price: $80 − $16 = $64
Answer: You save $16, and the final price is $64.
Example: What is 35% off $250?
- Convert 35% to a decimal: 0.35
- Find savings: $250 × 0.35 = $87.50
- Find the sale price: $250 − $87.50 = $162.50
Answer: You save $87.50, and the final price is $162.50.
Example: What is 10% off $45?
- Convert 10% to a decimal: 0.10
- Find savings: $45 × 0.10 = $4.50
- Find the sale price: $45 − $4.50 = $40.50
Answer: You save $4.50, and the final price is $40.50.
Find the original price from a sale price
If you know the sale price and the discount percentage, divide the sale price by the percentage of the original price that remains after the discount.
Example: A $72 sale price reflects a 20% discount
- Convert 20% to a decimal: 0.20
- Find the remaining portion: 1 − 0.20 = 0.80
- Divide the sale price: $72 ÷ 0.80 = $90
Answer: The original price was $90.
Find the discount percentage from two prices
When you know the original price and sale price, find the savings first. Then divide the savings by the original price and multiply by 100.
Example: An item falls from $150 to $120
- Find savings: $150 − $120 = $30
- Divide by the original price: $30 ÷ $150 = 0.20
- Convert to a percentage: 0.20 × 100 = 20%
Answer: The item is discounted by 20%.
How stacked discounts work
When two percentage discounts apply one after another, the second discount applies to the already reduced price. You cannot usually add the percentages together.
Example: 20% off, then another 10% off
- Start with $100.
- Apply 20% off: $100 × 0.80 = $80.
- Apply 10% off the new price: $80 × 0.90 = $72.
- Total savings: $100 − $72 = $28.
Answer: The combined discount is 28%, not 30%.
Discounts, tax, and fees
A store generally calculates a percentage discount from the listed price, then applies applicable sales tax to the discounted price. The final amount due may also include shipping, delivery, service, or other fees.
Use the Sales Tax Calculator to estimate tax after calculating the discounted price. Always check the seller’s specific terms for coupons, exclusions, and rounding rules.
Frequently asked questions
How do I calculate 20% off?
Multiply the original price by 0.20 to find savings, then subtract that amount from the original price. Alternatively, multiply the original price by 0.80 to get the sale price directly.
What is the easiest way to calculate a discount?
Convert the discount to the percentage you pay. For a 25% discount, you pay 75%, so multiply the original price by 0.75.
How do I find the original price after a discount?
Divide the sale price by one minus the discount rate as a decimal. For example, after a 25% discount, divide the sale price by 0.75.
Are 20% off and then 10% off the same as 30% off?
No. The second discount applies to the lower, already discounted price. A 20% discount followed by 10% off produces a combined discount of 28%.
Does sales tax apply before or after a discount?
Sales tax is commonly calculated from the discounted selling price, but the exact treatment depends on the seller and local tax rules.