Discount Calculator

This calculator handles three common discount scenarios:

• % Off: Enter the original price and discount percentage. Instantly see your savings and the final price. Perfect for figuring out what you will pay at checkout.
• Final Price: Enter the original price with both a percentage discount and an additional fixed dollar discount. Useful when a store offers "20% off plus $5 off your next purchase."
• Original Price: Enter the sale price and the discount percentage to find the original retail price. Useful for checking if a "sale" is real or if the original price was inflated.

The stacked discounts section shows why two sequential discounts are not the same as adding them. A 20% discount followed by a 10% discount equals a 28% effective discount, not 30%.

Final price from percentage off:

Savings = Original Price × (Discount % / 100) Final Price = Original Price - Savings = Original Price × (1 - Discount % / 100)

Example: $100 at 20% off. Savings = $20. Final price = $80.

Original price from sale price:

Original Price = Sale Price / (1 - Discount % / 100)

Example: Sale price $80, 20% off. Original = $80 / 0.80 = $100.

Stacked discounts:

Effective Discount = 1 - (1 - d1)(1 - d2) = d1 + d2 - d1×d2

20% then 10%: effective = 0.20 + 0.10 - 0.02 = 0.28 = 28% (not 30%). The second discount applies to an already-reduced price, so the combined effect is always less than the sum.