Discount Calculator
Percent off, final price, savings — and stacked discounts done right.
How this is calculated
final = price × (1 − d₁) × (1 − d₂) · stacked discounts multiply, never add
Worked example: R799 at 25% off → you pay R599.25, saving R199.75. Stack a further 10% and you pay R539.33 — an effective 32.5% off, not 35%, because the second discount applies to the already-reduced price. That multiplication is the entire secret of "extra % off" signage.
Frequently asked questions
How do I work out a percentage discount?
Multiply the price by the percent and divide by 100: 25% off R799 saves 799 × 0.25 = R199.75, leaving R599.25. The calculator shows both the saving and the final price live.
How do stacked discounts work — 20% off then 10% off?
They multiply, not add: 20% then 10% leaves 0.8 × 0.9 = 0.72 of the price — a 28% total discount, not 30%. Toggle "Stack a second discount" to compute it correctly; the difference is exactly the trick retail signage plays.
Is 50% off then 50% off free?
No — it is 75% off: half of a half is a quarter of the original. Each discount applies to the already-reduced price, which is why stacked percentages never add up the way they read.
How do I find the original price from a sale price?
Divide by (1 − discount): a R599.25 sale price after 25% off was 599.25 ÷ 0.75 = R799. Working backwards is the same trap as VAT — never add the percent back, always divide.