Calculate Discount
Enter a price, pick or slide a discount, and see your savings instantly. Stack a second discount or add sales tax for the full picture.
How Discounts Are Calculated
Discount Calculator is a tool that computes the final price after applying one or more percentage discounts to an original price. It shows total savings and, optionally, adds sales tax to the discounted price.
Single discount formula
A single percentage discount uses this formula:
- Savings = Original Price x (Discount % / 100)
- Final Price = Original Price - Savings
Equivalently: Final Price = Original Price x (1 - Discount% / 100)
Stacked (multiple) discounts
When two or more discounts apply sequentially -- such as a store sale plus a coupon -- each discount is applied to the already-reduced price, not the original. This means the combined reduction is always less than the sum of the individual percentages.
- Final Price = Original x (1 - d1/100) x (1 - d2/100) x ...
- Total Discount % = (1 - Final Price / Original) x 100
Sales tax after discount
In most retail scenarios, sales tax is calculated on the discounted price. This calculator follows that standard:
- Tax = Discounted Price x (Tax Rate / 100)
- Price After Tax = Discounted Price + Tax
Worked Examples
Simple percentage off
A $120 jacket is 25% off.
Savings = $120 x 0.25 = $30
Final price: $90.00
Stacked discounts
$200 shoes: 30% sale + 15% coupon.
After 30%: $200 x 0.70 = $140
After 15%: $140 x 0.85 = $119.00
Total saved: $81 (40.5% off, not 45%)
Discount + sales tax
$50 item, 20% off, 8% tax.
After discount: $50 x 0.80 = $40
Tax: $40 x 0.08 = $3.20
You pay: $43.20
Finding the discount %
Original $75, sale price $56.25.
Savings = $75 - $56.25 = $18.75
Discount = ($18.75 / $75) x 100 = 25% off
Common Mistakes
- Adding stacked discounts together. 20% off + 10% off does not equal 30% off. The second discount applies to the reduced price, giving 28% total.
- Applying tax to the original price. Tax should be calculated on the price after discounts, not before. Calculating on the original overstates what you owe.
- Confusing "percent off" with "percent of." 25% off $80 means you pay 75% of $80 ($60). 25% of $80 is $20 -- the savings amount, not the price.
- Rounding too early. When chaining multiple discounts, keep full precision until the final result, then round to two decimal places.
Discount Calculator FAQ
How do I calculate a percentage discount?
Multiply the original price by the discount percentage divided by 100 to get the savings. Subtract that from the original price. Formula: Final Price = Original Price x (1 - Discount% / 100). Example: 25% off $80 -- $80 x 0.75 = $60.
How do stacked discounts work?
Each discount is applied to the already-reduced price, not the original. A 20% discount followed by 10% off does not equal 30% off. Instead: $100 x 0.80 x 0.90 = $72. The total discount is 28%, not 30%.
Is 20% + 10% off the same as 30% off?
No. Stacked discounts always produce a smaller reduction than adding the percentages. 20% then 10% = 28% total off. The formula: Total Discount = 1 - (1 - d1) x (1 - d2).
Is sales tax calculated before or after the discount?
In most places, sales tax applies to the discounted price, not the original. A $100 item at 20% off with 8% tax: tax is on $80, not $100, so tax = $6.40.
Does the order of stacked discounts matter?
No. Multiplication is commutative: 20% off then 10% off gives the same result as 10% off then 20% off. Both = Original x 0.80 x 0.90.
How do I find the discount percentage from two prices?
Use: Discount % = ((Original - Sale Price) / Original) x 100. Example: Original $120, sale $90 -- ((120 - 90) / 120) x 100 = 25%.
What is the difference between discount and markup?
Discount reduces a price from the customer's perspective. Markup increases cost from the seller's perspective. A 50% markup on $100 cost = $150 selling price. A 50% discount on $150 = $75. They use different base numbers. See our markup calculator for details.
Can I use this for "buy one get one" deals?
A "buy one get one 50% off" deal on a $40 item means you pay $40 + $20 = $60 for two items. That is $60 / 2 = $30 per item, or 25% off per item. Enter the per-item discount here to see the savings.
Related Tools
- Percentage Calculator -- calculate any percentage of a number
- Percentage Change Calculator -- find the percent increase or decrease between two values
- Markup Calculator -- calculate selling price from cost and markup
- Margin Calculator -- find profit margin from cost and revenue
- Sales Tax Calculator -- compute tax on a purchase
Privacy & Limitations
- All calculations run entirely in your browser -- nothing is sent to any server.
- Results are estimates for planning purposes and should not replace professional financial advice.
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Discount Calculator FAQ
How do I calculate a percentage discount?
Multiply the original price by the discount percentage divided by 100 to get the savings amount. Subtract the savings from the original price to get the final price. Formula: Final Price = Original Price × (1 − Discount% ÷ 100). Example: 25% off $80 → $80 × (1 − 0.25) = $60.
How do stacked discounts work?
Stacked discounts are applied one after another, not added together. A 20% discount followed by an extra 10% off does not equal 30% off. Instead, you first apply 20% to the original price, then apply 10% to the already-reduced price. Example: $100 with 20% then 10% → $100 × 0.80 × 0.90 = $72 (28% total, not 30%).
Is 20% off plus 10% off the same as 30% off?
No. Stacked discounts produce a smaller total reduction than adding the percentages. 20% + 10% stacked = 28% total off, not 30%. This is because the second discount applies to the already-reduced price. The formula is: Total Discount = 1 − (1 − d1) × (1 − d2), where d1 and d2 are the discounts as decimals.
Is sales tax calculated before or after the discount?
In most jurisdictions, sales tax is calculated on the discounted (final) price, not the original price. If an item is $100 with 20% off, sales tax applies to $80. This calculator applies tax after all discounts, which matches standard retail practice.
What is the formula for discount percentage from two prices?
To find what percentage discount was applied: Discount % = ((Original Price − Sale Price) ÷ Original Price) × 100. Example: Original $120, sale $90 → ((120 − 90) ÷ 120) × 100 = 25% off.
Does the order of stacked discounts matter?
No. Mathematically, the order of multiplication does not matter. Applying 20% off then 10% off gives the same result as 10% off then 20% off. Both equal Original Price × 0.80 × 0.90. The final price is identical regardless of order.