Utility Stack
Free shopping calculator
Calculate the sale price, amount saved, tax, and final checkout total for any percentage-off deal.
Deal result
Multiply the original price by the discount percentage to find the amount saved, then subtract that savings from the original price. For example, 25% off $100 saves $25 and leaves a sale price of $75.
If you are comparing a shelf tag, coupon, and checkout total, calculate the first discount before estimating tax. That makes it easier to see whether the final register total matches the deal you expected.
When a store offers an extra coupon, the second discount usually applies to the already-discounted price. A 20% discount followed by an extra 10% coupon is not the same as 30% off; it is an effective 28% discount.
Flat coupons work differently because they subtract a set currency amount. A $10 coupon matters more on a $40 item than on a $200 item, so switch the coupon mode when a store gives dollars off instead of percent off.
Stacked deals are easier to understand when each step is calculated in order. Start with the original price, apply the advertised discount, apply any extra coupon, then estimate tax on the discounted subtotal if tax applies.
| Deal | How it is applied | Result on $100 |
|---|---|---|
| 25% off | $100 x 0.75 | $75.00 before tax |
| 25% off plus extra 10% | $100 x 0.75 x 0.90 | $67.50 before tax |
| 25% off plus $10 coupon | ($100 x 0.75) - $10 | $65.00 before tax |
| Buy two with same discount | Discount each item, then multiply by quantity | $150.00 before tax at 25% off |
To reverse-calculate the discount, subtract the sale price from the original price, divide by the original price, and multiply by 100. This calculator does that in the compare sale price field.
This is useful when a tag shows the sale price but not the actual discount. It also helps compare clearance items where two stores use different original prices for similar products.
Common mistakes include adding stacked percentages together, forgetting that tax may apply after the discount, treating a rebate like an instant discount, or applying a coupon to each item when it only applies once per order.
Read coupon exclusions before assuming the result applies to every product. Some discounts exclude clearance, gift cards, electronics, shipping, or certain brands.
Shipping and handling can also change the real deal. A store with a smaller discount and free shipping may beat a larger discount once delivery fees are included.
A bigger percentage off is not always the lowest final price if the original price is inflated. Use the final checkout total, unit price, and quantity needed to decide whether the deal is actually useful.
For groceries, household goods, and subscriptions, compare the unit price after discount. For clothing, electronics, and furniture, compare the final checkout price against recent prices from other stores, not only against the crossed-out original price.
An instant discount lowers the amount you pay today. A rebate or store credit may require a later claim, a future purchase, or a qualifying account. If a deal depends on getting money back later, calculate both the checkout total and the after-rebate total before deciding.
For budgeting, the checkout total is usually the safer number because that is what leaves your account now. Treat future rewards as a bonus unless you are certain you will use them.