How to use the Discount Calculator
- Enter the original price — the price before any discount. No currency symbol is needed; the calculator works for any currency.
- Enter the discount percentage. For "30% off", type 30.
- Optionally add an extra discount or sales tax. An extra discount is applied to the already-reduced price. Sales tax is added at the end, which is how tax is charged at most checkouts in places that add tax on top of the shelf price.
- Read the three results: how much you save, the sale price, and the total you will actually pay.
What this calculator does
Sale signs are designed to be read quickly, not calculated accurately. The Discount Calculator turns a percentage off into real money, so you can compare offers, check a receipt, or decide whether "buy now" is really a bargain. It also shows the overall discount when two discounts are stacked, which is almost always smaller than it first appears.
How discounts are calculated
discount amount = original price × discount % ÷ 100
sale price = original price − discount amount
For a 25% discount on 79.99: 79.99 × 25 ÷ 100 = 20.00 (rounded to the cent), so the sale price is 59.99.
Stacked discounts
When a store offers "an extra 10% off sale prices", the second discount is taken from the reduced price, not the original:
final price = price × (1 − d1 ÷ 100) × (1 − d2 ÷ 100)
So 30% off followed by an extra 10% off is not 40% off. On a 100.00 item: 100 × 0.70 = 70.00, then 70 × 0.90 = 63.00 — an overall discount of 37%. The calculator shows this combined percentage for you.
Sales tax
total = sale price × (1 + tax % ÷ 100)
Tax is charged on the discounted price, so the discount also reduces the tax you pay. If prices where you live already include tax (as with VAT or GST in many countries), leave the tax field empty.
Examples
| Offer | Original | You save | Sale price | With 8% tax |
|---|---|---|---|---|
| 20% off | 50.00 | 10.00 | 40.00 | 43.20 |
| 35% off | 120.00 | 42.00 | 78.00 | 84.24 |
| 30% + extra 10% off | 100.00 | 37.00 | 63.00 | 68.04 |
| 15% off | 899.00 | 134.85 | 764.15 | 825.28 |
Tips for comparing deals
- Compare final prices, not percentages. 40% off a 150 jacket (90) costs more than 25% off a 100 jacket (75).
- Watch for inflated "original" prices. A discount is only meaningful if the original price is one the item actually sold for.
- Include delivery. Add shipping to the total before comparing an online deal with a local one.
- Work backwards when you need to. To find the original price from a sale price, divide by (1 − discount ÷ 100): a 60.00 sale price after 25% off came from 60 ÷ 0.75 = 80.00.
For other percentage questions — like how much a price has risen — use the Percentage Calculator, and see our guide to calculating percentages for more discount examples and common mistakes.
Frequently asked questions
How do I calculate a discount?
Multiply the original price by the discount percentage and divide by 100 to get the amount saved, then subtract that from the original price. 20% off 45 is 45 × 20 ÷ 100 = 9, so you pay 36.
Is 20% off plus an extra 20% off the same as 40% off?
No. The second discount applies to the already-reduced price, so the total discount is 36%, not 40%. On a 100 item you would pay 64, not 60.
Should tax be calculated before or after the discount?
In most places that add sales tax at checkout, tax is calculated on the discounted price. That is what this calculator does. If your prices already include tax, leave the tax field empty.
How are results rounded?
Money values are rounded to two decimal places. Because each step is rounded as it would be on a receipt, a result may occasionally differ by one cent from a calculation done without rounding.
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