Discount Calculator
Work out sale prices and savings from a percentage off, reverse a discount from a sale price, or stack two discounts to find the true effective discount — with optional tax.
Written and reviewed by the CalcBundle editorial team. Transparent formulas · results are estimates, not advice.
Sale price
Enter an original price greater than zero.
What is a discount calculator?
A discount calculator turns an original price and a discount into a sale price and savings — and back again. It also handles the tricky case of stacked discounts, where the maths is not what most people expect.
How to calculate a discount
- Discount amount = Original price × discount %
- Sale price = Original price − discount amount
- Reverse: discount % = (original − sale) ÷ original × 100
Multiple (stacked) discounts
This is the part people get wrong. Two discounts multiply, they do not add. A 20% discount followed by an extra 10% is not 30% off:
- $100 − 20% = $80
- $80 − 10% = $72
- Effective discount = 28%, not 30%
Percentage off vs final price
The calculator shows both the amount saved and the effective percentage, so you can compare offers fairly. To make sure a promotion is still profitable, check it against your profit margin and price with the product pricing calculator.
Example
A $100 product at 20% off costs $80, saving $20. Stack another 10% and it costs $72 — a true 28% discount.
Frequently asked questions
How do you calculate a discount?
Discount amount = original price × discount %. Sale price = original price − discount. For a $100 item at 20% off, the discount is $20 and the sale price is $80.
How do multiple (stacked) discounts work?
Stacked discounts are multiplicative, not additive. 20% off then 10% off is not 30% off — it is $100 → $80 → $72, an effective discount of 28%.
How do I find the percentage off from a sale price?
Discount % = (original − sale) ÷ original × 100. From $100 down to $80, that is 20% off.
Should tax be applied before or after the discount?
It depends on the jurisdiction and retailer. This calculator supports both: applying tax after the discount (most common) or to the original price before the discount.
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Disclaimer. This calculator provides estimates for informational purposes only. Results are based on the information you enter and the assumptions used by the calculator. Actual financial, tax, business valuation, lending, marketplace or investment outcomes may differ. Consider consulting a qualified professional for decisions involving significant amounts of money. Results are estimates. Tax treatment of discounts varies by jurisdiction and retailer.