How to Calculate Discount: Percentages, Stacking, and Reverse Calculations

The Basic Formula

Calculating a percentage discount is straightforward: multiply the original price by the discount rate, then subtract the result from the original price.

Or in one step: Final Price = Original Price × (1 − Discount % ÷ 100)

Example: 30% Off $250

Discount amount: $250 × 0.30 = $75. Final price: $250 − $75 = $175. Alternatively: $250 × 0.70 = $175.

Stacking Discounts (Successive Discounts)

When two discounts are applied in sequence — say 20% off, then an additional 10% off — they do not add up to 30%. The second discount applies to the already-reduced price.

The general formula for stacked discounts: multiply the complements together. For discounts of d₁ and d₂:

Finding the Original Price from a Discounted Price

If you know the final price and the discount percentage, you can reverse the calculation:

Example: You paid $67.50 after a 25% discount. What was the original price? $67.50 ÷ 0.75 = $90.

Discount as a Fraction

Some common discounts map to simple fractions, which makes mental math easier:

Business Applications

Discounts are not just about consumer sales. Businesses use percentage discounts in trade pricing (wholesale vs retail), early payment terms (e.g. “2/10 net 30” means a 2% discount for paying within 10 days), volume discounts, and promotional campaigns. Understanding the math ensures you know the real impact on your margins.

A 20% discount on a product with a 30% margin wipes out two-thirds of your profit. Always calculate the margin impact before setting discount levels.

Try the Discount Calculator to compute any percentage discount, or check the impact on your bottom line with the Margin Calculator.