Discount Calculator
Find the sale price and amount saved on a discounted item, or work backward from a sale price to find the discount percentage. Results update live as you type.
How to Use the Discount Calculator
- Choose a mode: "I know the discount %" or "I know the sale price."
- In the first mode, enter the original price and discount percentage to see the sale price and savings.
- In the second mode, enter the original price and the sale price to work out the discount percentage.
- Results update instantly as you adjust any value.
Why Use This Tool?
How is the sale price calculated?
Sale Price = Original Price × (1 − Discount % ÷ 100). Amount Saved is simply the Original Price minus the Sale Price. This is the standard method retailers use to calculate markdown pricing during sales and promotions.
How does the reverse mode work?
If you already know the sale price and the original price — for example, from a receipt or price tag — the reverse mode calculates the discount percentage using: Discount % = (1 − Sale Price ÷ Original Price) × 100. This is useful for comparing how good a deal actually is across different stores.
Can I use this for stacked or multiple discounts?
This calculator handles a single discount percentage at a time. For stacked discounts (e.g. 20% off, then an additional 10% off), apply the first discount, use the resulting sale price as the new "original price," and calculate the second discount separately — discounts are not simply additive.
Is this tool free and private?
Yes, completely free with no signup. All calculations run locally in your browser using JavaScript — nothing you enter is uploaded, logged or stored.