How to Calculate a Discount

Multiply the price by the share you pay. If an item is 35% off, you pay 100% − 35% = 65% of the price:

The two-step way also works: find the discount (120 × 0.35 = $42), then subtract it (120 − 42 = $78). The one-step way is quicker and leaves less room for mistakes.

Standing in a store, start from 10%: move the decimal point one place left. Then build the discount you need:

• 20% off $45: 10% is $4.50, so 20% is $9. You pay $36.
• 30% off $70: 10% is $7, so 30% is $21. You pay $49.
• 15% off $60: 10% is $6, plus half of that ($3), so 15% is $9. You pay $51.
• 50% / 25% off: halve the price, or halve it twice.

Round awkward prices first: $49.99 is about $50, so 30% off is about $35.

"40% off clearance, plus an extra 20% off at the register" is not 60% off. The extra discount comes off the already-reduced price, so multiply the shares you pay:

On a $90 item that is 90 × 0.48 = $43.20, not the $36 you would pay at a true 60% off. Stacked discounts are always worth less than their sum, though you still save more than with either one alone.

To compare "$10 off" with "20% off", find the price where they are equal: $10 is 20% of $50.

• Below $50, the $10 coupon wins. On a $40 item it saves $10 (25%), while 20% off saves $8.
• Above $50, the percent wins. On an $80 item 20% off saves $16, while the coupon still saves $10.

The break-even price is always the dollar amount ÷ the percent as a decimal, here 10 ÷ 0.2 = $50.

Turn the deal into a percent off the total by comparing what you pay with the full price of everything you take home (assuming the items cost the same):

A multi-buy deal only saves money if you would have bought all the items anyway.

In most places, sales tax is charged on the price after store discounts. Apply the discount first, then the tax:

Because both steps are multiplications, the order doesn't change the final number. What changes is how much tax you pay: $4.80 on $60 instead of $6.40 on $80. Rules for manufacturer coupons vary, so check your receipt. The Sales Tax Calculator handles the tax step, and How to Calculate Sales Tax covers it in depth. Eating out? See how to calculate a tip.

Was it really a discount? Divide the savings by the original price:

What was the original price? Divide what you paid by the share you paid. If a receipt shows $56 after 30% off, the original was 56 ÷ 0.7 = $80. Don't add 30% back on: 56 × 1.3 = $72.80, which is wrong.

Try each one, then open the answer.

1. What is 35% off $120?
   Show answer

   120 × 0.65 = $78
2. A jacket was $90 and is now $63. What percent off is that?
   Show answer

   27 ÷ 90 × 100 = 30% off
3. You paid $56 after 30% off. What was the original price?
   Show answer

   56 ÷ 0.7 = $80
4. A $200 item is 20% off, then an extra 15% off. What do you pay, and what is the total discount?
   Show answer

   200 × 0.8 × 0.85 = $136, which is 32% off
5. On a $40 item, which is better: $10 off or 20% off?
   Show answer

   $10 off ($30 vs $32), because $40 is below the $50 break-even
6. Two $30 shirts are "buy one, get one 50% off". What percent do you save?
   Show answer

   You pay $45 of $60, so you save 25%