Discount Calculator

How to use this discount calculator

Enter the original price of the item and the discount percent advertised. The calculator instantly shows the sale price, how much you save in dollars, and the effective discount. Open Advanced to add a second stacked discount — like an extra coupon applied on top of a sale — and a sales tax rate to see the real out-the-door total at checkout.

How this is calculated

We apply each discount in sequence to the price. The first discount gives price × (1 − discount%). A second discount is then taken off that already-reduced number, not off the original. Finally, sales tax is added to the discounted price. Your savings is the original price minus the discounted price (before tax), and the effective discount is the total percentage off the original once both discounts are combined.

Worked example: why two 20% discounts are not 40% off

Say a jacket lists at $100. The store offers 20% off, then hands you a coupon for an extra 20% off. It is tempting to add them and assume 40% off — but discounts stack multiplicatively, not additively. The first 20% brings the price to $80. The second 20% comes off that $80, not the original $100, taking it to $64. That is a true saving of $36, or an effective discount of 36% — not 40%. The shortcut to remember: multiply the remaining fractions, so 0.80 × 0.80 = 0.64, meaning you pay 64% and save 36%.

Discount tips and common mistakes

• Stacked discounts always compound — the second percent is taken off a smaller number, so combined savings are less than the simple sum.
• Tax comes last — sales tax is applied to the discounted price, so a bigger discount also shrinks the tax you owe.
• Watch "up to" claims — advertised maximum discounts often apply only to select items, not your cart.
• Compare unit price, not just percent off — a large percentage off an inflated original can still cost more than a competitor.

Once you know your discounted price, our sales tax calculator can break down the tax portion for any local rate.