How to calculate a discount
- Enter the original price.
- Pick a percentage or type your own; add an extra discount if there is one.
- Add the sales tax rate to see the final amount at the register.
The formula
Sale price = original price Γ (1 β discount Γ· 100). The amount saved is the original price minus the sale price. For a $120 item at 35% off: 120 Γ 0.65 = $78, so you save $42.
Stacked discounts and coupons
When a coupon applies after a sale, the discounts multiply rather than add. 30% off and then 20% off is 1 β 0.7 Γ 0.8 = 44% off, not 50%. The calculator shows the true total percentage.
Spotting a real deal
Compare the final price, not the percentage. "Buy one, get one 50% off" is 25% off each item, and a bigger discount on an inflated list price may cost more than a smaller one elsewhere. Remember shipping and tax.
Frequently asked questions
How do I calculate percent off?
Multiply the price by the discount as a decimal and subtract it: $80 with 25% off is 80 β 80 Γ 0.25 = $60.
Are two discounts added together?
No. 20% off then an extra 10% off is 1 β 0.8 Γ 0.9 = 28% off, not 30%.
Is sales tax charged on the original or sale price?
In the US, sales tax is usually charged on the discounted price for store discounts.
How do I find the original price from the sale price?
Divide the sale price by 1 minus the discount: $60 after 25% off came from 60 Γ· 0.75 = $80.