Discount Calculator

Multiply the original price by (1 − discount/100). For a 30% discount on a $50 item: $50 × (1 − 0.30) = $50 × 0.70 = $35. Alternatively, calculate the discount amount (30% of $50 = $15) and subtract it from the original price ($50 − $15 = $35).

Divide the discount amount by the original price and multiply by 100. Discount % = ((original − sale) ÷ original) × 100. For example, an item originally $80 on sale for $60: ((80 − 60) ÷ 80) × 100 = 25% off.

Stacked discounts are applied sequentially, not added together. A 20% discount followed by a 10% discount does not equal 30% off — it equals 28% off total. After the first 20% discount, the second 10% is calculated on the already-reduced price, so the combined saving is 1 − (0.8 × 0.9) = 0.28 or 28%.

Markdown (discount) reduces the selling price from the original retail price. Markup increases a cost price to arrive at a selling price. For example, a 50% markup on a $10 cost gives a $15 selling price, while a 50% markdown from $15 gives a $7.50 sale price. They are calculated from different base values.

For 10% off, move the decimal point one position to the left. For 25% off, divide by 4. For 20% off, find 10% and double it. For 15% off, find 10%, halve it to get 5%, and add them together. These mental shortcuts work well for quick shopping estimates without a calculator.