Free Discount Calculator: Percent Off, Sale Price and Savings
Find the sale price and how much you save for any percent off, including stacked discounts like "an extra 10% off sale prices", several items and sales tax. With the formulas and the reason two discounts never simply add up.
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A "25% off" sign is easy to read, but "an extra 15% off already reduced prices" or a sale price plus sales tax takes a little more math. This free discount calculator shows the sale price, what you save and the total discount for one or two discounts, any quantity and sales tax, so you know exactly what you will pay.
Discount calculator
Prices are rounded to the cent after each discount, the way most stores do it. Sales tax is charged on the discounted price, which is how most states treat a store discount.
Key takeaways
- 25% off an $80 item: you save $20 and pay $60.
- An extra 10% off that sale price brings it to $54, a total discount of 32.5%, not 35%.
- With 8.25% sales tax on the $54 sale price, you pay $58.46.
How to calculate a discount
Sale price = original price × (1 − discount)
For 25% off $80: $80 × 0.75 = $60. The savings are $80 × 0.25 = $20. A quick mental shortcut is to find 10% by moving the decimal point one place ($8.00) and then multiply: 25% is 2.5 × $8 = $20.
To find the percent off from two prices, divide the savings by the original price: ($80 − $60) ÷ $80 = 25%.
Why stacked discounts do not add up
When a second discount applies to the already reduced price, the two percentages multiply instead of adding:
Total discount = 1 − (1 − first discount) × (1 − second discount)
| Offer | Total discount | $100 item costs |
|---|---|---|
| 20% off, then an extra 10% | 28% | $72.00 |
| 25% off, then an extra 10% | 32.5% | $67.50 |
| 30% off, then an extra 20% | 44% | $56.00 |
| 50% off, then an extra 50% | 75% | $25.00 |
The order does not matter: 10% off and then 20% off gives the same price as 20% off and then 10%.
Sales tax on discounted prices
When a store gives the discount, sales tax is generally charged on the reduced price you actually pay. Manufacturer coupons and rebates can be treated differently, because the store may still be paid the full price, and some states tax the price before those discounts. The calculator applies the tax to the sale price; use the sales tax calculator for more detail on rates.
Is it really a bargain?
- Compare the final price, not the percentage. 40% off a high list price can still cost more than another store's regular price.
- Watch "former price" claims. Federal Trade Commission guidance says a former price is a fair basis for a comparison only if it was the actual price offered to the public on a regular basis for a reasonably substantial period.
- Count the full cost: shipping, membership fees and interest on a buy now, pay later plan or a credit card balance can wipe out the savings.
- Buy what you planned. A discount only saves money on something you would have bought anyway; put the difference toward a savings goal.
For sellers: what a discount really costs
A discount comes straight out of your profit. A product with a 30% margin that you sell 10% cheaper loses a third of its profit, and a 25% discount leaves only $2.86 of the $17.14 profit on a $57.14 item that costs $40. Check the effect with the profit margin calculator before you run a sale.
Frequently asked questions
How do I calculate 20% off?
Multiply the price by 0.80. For a $45 item: $45 × 0.80 = $36, which saves you $9.
Is 20% off plus 10% off the same as 30% off?
No. The extra 10% applies to the reduced price, so the total discount is 28%. On a $100 item you pay $72, not $70.
How do I find the percent off from the sale price?
Subtract the sale price from the original price and divide by the original price. A $120 jacket on sale for $90: $30 ÷ $120 = 25% off.
How do I find the original price?
Divide the sale price by 1 minus the discount. A $60 sale price at 25% off: $60 ÷ 0.75 = $80.
Is sales tax charged before or after a discount?
For store discounts, generally after: you pay tax on the reduced price. Coupons reimbursed by a manufacturer can be taxed on the price before the coupon in some states.
