Work out what you'll actually pay
A "30% off" sign tells you the discount but not the price. To know what leaves your wallet, you need the sale price, and ideally the exact amount you save. Doing it in your head is fine for round numbers, but it gets fiddly fast with odd percentages, a coupon stacked on top of a sale, or sales tax added at the register.
This guide shows the simple formula so you can do it anywhere, then points you at a faster way when the numbers get messy or you're standing in a store comparing two deals.
How to calculate a discount and sale price
The math is two short steps:
- Find the discount amount. Multiply the original price by the discount percentage written as a decimal. For 25% off a $80 jacket: 80 × 0.25 = $20 off.
- Subtract it from the original price. 80 − 20 = $60 sale price. That's it: original price minus discount equals what you pay.
A shortcut that skips a step: multiply the original price by (100 − discount%) ÷ 100. For 25% off, that's 80 × 0.75 = $60 directly.
If you'd rather not juggle decimals, open the discount calculator and let it do the arithmetic:
- Enter the original price (for example, 80).
- Leave the discount type on % Off, or switch to Fixed if the coupon is a flat dollar amount instead.
- Type the discount, or tap a preset like 10%, 25%, or 50%. The sale price, the dollar amount saved, and the effective percentage update instantly below.
- Selling in pounds, euros, or rupees? Pick your currency at the top so the symbols and rounding match.
- Hit the copy button to grab the full breakdown (original, discount, sale price) as text for a note or message.
The calculation runs entirely in your browser. The numbers you type stay on your device, nothing is uploaded, and there's no sign-up.
Adding tax to the sale price
Discounts usually apply before tax, so the right order is: take the discount first, then add tax to the lower price. In the calculator, tick Add tax after discount and enter your rate. For a $60 sale price at 8.25% tax: 60 × 0.0825 = $4.95 tax, for a total of $64.95. If you frequently work the other way, separating a tax-inclusive price into its parts, the dedicated sales tax calculator handles that cleanly.
Working backwards or comparing deals
The same tool covers a few cases plain mental math doesn't:
- Find the original price from a sale price and discount (the Original Price tab). If you paid $80 after 20% off, the original was 80 ÷ 0.80 = $100.
- Find the discount percent when you only know the two prices (the Find % tab): (original − sale) ÷ original × 100.
- Stack coupons to see how "20% off, then an extra 10% off" really lands. Stacked discounts apply one after another, not added together, so 20% + 10% is not 30% off, it's 28% (the second cut comes off the already-reduced price).
- Compare two deals side by side, including price per unit, in the Best Deal tab.
Tips
- Stacked discounts never simply add up. Two coupons of 20% and 10% give 0.80 × 0.90 = 0.72, so 28% off, not 30%. The bigger the percentages, the bigger this gap, so always multiply rather than sum.
- A flat-dollar coupon is a bigger percentage on a cheaper item. $10 off a $40 item is 25%; the same $10 off a $200 item is only 5%. Use the Find % tab to compare offers fairly.
- Round to sanity-check. 30% off is "a bit less than a third off." If the calculator says you save almost half on a 30% deal, you've mistyped something.
- Discount first, tax second is the standard register order and gives you the lower total. Calculating tax on the full price before the discount overstates what you'll pay.
Common problems
- Confusing "% off" with "% of." 30% off means you pay 70% of the price. If you multiply by 0.30 and stop, you've found the discount, not the sale price; subtract it from the original.
- A discount over 100%. A percentage can't take a price below zero. If you see a free result, the discount value is likely wrong, or a fixed-dollar coupon exceeds the item's price.
- Forgetting quantity. A per-item discount on a 3-pack saves three times as much. Use the cart view or multiply the per-item saving by the count.
FAQ
What's the formula for sale price? Sale price = original price × (1 − discount% ÷ 100). For 40% off, multiply by 0.60. To get the saving alone, multiply the original by the discount as a decimal (× 0.40).
How do I find the original price from a sale price? Divide the sale price by (1 − discount% ÷ 100). Paid $45 after a 25% discount? 45 ÷ 0.75 = $60 original. The Original Price tab does this for you.
Is 20% off plus another 10% off the same as 30% off? No. Stacked discounts multiply, so 20% then 10% is 0.80 × 0.90 = 0.72, a 28% effective discount. You always pay slightly more than a single combined percentage would suggest.
Does the discount or the tax come first? Discounts almost always apply before sales tax, which means tax is charged on the reduced price. That's the cheaper order and the one the calculator uses when you enable tax.
For more everyday money math, try the percentage calculator for any "what percent of" question, or the tip calculator when you're splitting a bill.