How to Calculate a Discount
A discount reduces the price by a percentage of the original. The savings are the original price times the rate; the sale price is what remains. The fastest mental method is to think in terms of what you pay rather than what you save: 30% off means you pay 70%.
Sale price = Price × (100 − Discount) ÷ 100
A $249 jacket at 35% off: you pay 65%, so 249 × 0.65 = $161.85, saving $87.15.
Why Stacked Discounts Don't Add Up
“30% off, plus an extra 20% off at checkout” tempts you to read 50% — but the second discount applies to the already-reduced price. The combined effect is 1 − (0.70 × 0.80) = 44% off. Retailers know the bigger-sounding stack sells; now you know the real number. This calculator shows the effective total discount whenever you use the extra-discount field.
Quick Reference
| Discount | You pay | On $100 |
|---|---|---|
| 10% | 90% | $90 |
| 25% | 75% | $75 |
| 33% | 67% | $67 |
| 50% | 50% | $50 |
| 30% + extra 20% | 56% | $56 |
| 50% + extra 50% | 25% | $25 |
In practice Working out whether a "70% off" sale really is
A jacket is marked $249, reduced by 50%, with a sign promising an extra 20% off at the till. Shoppers read that as 70% off. It isn't.
The first cut brings it to $124.50. The second applies to the reduced price: 124.50 × 0.80 = $99.60. That is a real discount of 60%, not 70% — the difference between the sign and the receipt is about $25.
Stacked offers always land above the sum of their parts. The quick check is to multiply what you pay: 0.50 × 0.80 = 0.40, so you pay 40% of the ticket price.
Frequently Asked Questions
How do I calculate a discount price?
Multiply the original price by the discount percentage divided by 100 to get the savings, then subtract from the original price. A $80 item at 25% off saves $20 and costs $60. Shortcut: multiply the price by (100 − discount) ÷ 100 — here 80 × 0.75 = 60.
How do stacked discounts like “extra 20% off clearance” work?
They apply one after another, not added together. 30% off then an extra 20% off is not 50% off: a $100 item goes to $70, then 20% off $70 gives $56 — an effective 44% total discount.
How much is 20% off of $50?
20% of $50 is $10, so the sale price is $40.
How do I work out the original price from a sale price?
Divide the sale price by (100 − discount) ÷ 100. If something costs $42 after 30% off, the original was 42 ÷ 0.70 = $60.
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The CalculatorsGuide Editorial Team. (2026). Discount Calculator. CalculatorsGuide. Retrieved from https://www.calculatorsguide.com/everyday/discount-calculator/