Percentage Discount Calculator
Calculate sale price, discount amount, and savings percentage for any original price.
QUICK DISCOUNT
What Is the Percentage Discount Calculator?
This discount calculator handles three modes: find the sale price from original price and discount %, find the discount percentage from original and sale prices, and find the original price from sale price and discount %. An optional tax field shows the final total including sales tax.
- ›Find Sale Price: Original price + discount % → savings and final price.
- ›Find Discount %: Original and sale price → how much percent was saved.
- ›Find Original Price: Sale price + discount % → what the item originally cost.
- ›Tax support: Add optional sales tax to any calculation for a complete checkout total.
- ›Quick discount buttons: 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 70%, 75% off.
Formula
| Mode | Formula | Example |
|---|---|---|
| Find Sale Price | Original × (1 − D%/100) | $100 at 20% off → $80 |
| Find Discount % | (Savings / Original) × 100 | $100 → $75: (25/100)×100 = 25% |
| Find Original Price | Sale ÷ (1 − D%/100) | $80 after 20% off → $100 |
| With tax | Sale × (1 + Tax%/100) | $80 + 8.5% tax → $86.80 |
How to Use
- 1Select a mode: Find Sale Price, Find Discount %, or Find Original Price.
- 2Click a quick discount button or type a custom discount percentage.
- 3Enter the required price(s) in the input fields.
- 4Optionally enter a tax rate to see the total including tax.
- 5Press Enter or click Calculate.
- 6Click Clear to reset.
Example Calculation
Finding the original price from a sale
Common mistake: calculating discount on sale price
Understanding Percentage Discount
How Discounts Are Calculated
A discount reduces the price by a percentage of the original price. The key formulas are: Sale = Original × (1 − d/100) and Savings = Original × d/100. Notice that both formulas use the original price as the base, not the sale price. This distinction matters when working backwards from a discounted price.
Stacked Discounts
Two discounts applied sequentially are not additive. A 20% discount followed by a 10% further discount is not 30% off:
For stacked discounts, multiply the remaining fractions: (1−0.20) × (1−0.10) = 0.72 → 28% total discount. Use this calculator sequentially by entering the intermediate result into a new calculation.
Discount vs Markup
Discount and markup use different bases. A 25% discount reduces from the original price. A 25% markup increases from the cost price. They are not inverses:
- ›Cost $80 with 25% markup: $80 × 1.25 = $100 retail
- ›$100 retail with 25% discount: $100 × 0.75 = $75 sale (not $80)
- ›To undo a 25% markup: divide by 1.25 (= 20% reduction of the retail price)
- ›Gross margin = (Sale − Cost) / Sale; markup = (Sale − Cost) / Cost
Frequently Asked Questions
How do I calculate the sale price after a discount?
Use Find Sale Price mode. Formula: Sale = Original × (1 − Discount%/100).
How do I find the original price from the sale price?
Use Find Original Price mode. Formula: Original = Sale ÷ (1 − Discount%/100).
Never subtract the discount percentage from the sale price, that applies the discount twice. Always divide by the complement factor.
How do I calculate the discount percentage?
Use Find Discount % mode. Formula: Discount% = ((Original − Sale) / Original) × 100.
How do I add tax to a discounted price?
Enter the tax rate in the optional Tax Rate field. Tax is applied to the sale price (after discount), then added:
Tax is applied after the discount, not to the original price. This is how retail checkout works in most jurisdictions.
What is the difference between a discount and a markup?
Discount reduces from retail/original price; markup increases from cost price. They use different bases:
How do stacked discounts work?
Sequential discounts multiply, they are not added. A 20% discount then 10% further discount is (0.80 × 0.90 = 0.72), a 28% total discount, not 30%:
To combine two discounts d₁ and d₂: combined% = 100 − (1−d₁/100)×(1−d₂/100)×100
Is 50% off the same as buy-one-get-one-free?
Yes, mathematically, if you buy two items and get one free, you pay for one and get two, which is equivalent to paying 50% of the total. However, BOGO requires buying two units while "50% off" applies to one unit. The per-unit cost is the same; the total cash outlay differs.