How to use the percent off calculator
- Enter the original price on the tag.
- Enter the percent off, such as 30 for a "30% off" sign.
- Enter your sales tax rate, or leave it blank if there is none.
- Read the sale price and the amount saved, then the price with tax. The table below shows the same item from 10% to 75% off.
How percent off is calculated
The quickest way to get the sale price is to multiply by the share you still pay. At 30% off you pay 70% of the price, so multiply by 0.70. Sales tax is added to the sale price, not the original price, because the store charges tax on what you actually pay.
Worked example
The calculator starts with a $120 jacket at 30% off, with 7% sales tax:
- Amount saved: $120 × 30 ÷ 100 = $36
- Sale price: $120 − $36 = $84.00 (or $120 × 0.70)
- Sales tax: $84 × 0.07 = $5.88
- Price with tax: $84 + $5.88 = $89.88
At full price with tax, the jacket would have cost $120 × 1.07 = $128.40, so the sale really saves you $38.52 at the register.
A few more checks you can try: 15% off $120 is $120 × 0.85 = $102.00. A $59.99 item at 40% off is $59.99 × 0.60 = $35.994, which rounds to $35.99. And 75% off $250 leaves a quarter of the price, $62.50.
Common sale percentages
What you pay at each discount, as a share of the original price, and what that means on a $120 item:
| Sign says | You pay | On a $120 item | With 7% tax |
|---|---|---|---|
| 10% off | 90% | $108.00 | $115.56 |
| 20% off | 80% | $96.00 | $102.72 |
| 25% off | 75% | $90.00 | $96.30 |
| 30% off | 70% | $84.00 | $89.88 |
| 40% off | 60% | $72.00 | $77.04 |
| 50% off | 50% | $60.00 | $64.20 |
| 60% off | 40% | $48.00 | $51.36 |
| 75% off | 25% | $30.00 | $32.10 |
Mental math shortcuts
- 10% off: move the decimal point one place left and subtract. 10% of $120 is $12, so the price is $108.
- 20% or 30% off: find 10% and multiply. 30% of $120 is 3 × $12 = $36.
- 25% off: take a quarter off. A quarter of $120 is $30, so the price is $90.
- 50% off: halve it. Then 75% off is half of that again.
Signs that say "an extra 20% off" on top of an existing sale are a stacked discount and come off the reduced price. For those, or for a dollar amount off, use the discount calculator.
Frequently asked questions
How do I calculate 30% off?
Multiply the price by 0.70, because you still pay 70% of it. A $120 item at 30% off costs $120 × 0.70 = $84, and you save $36.
Is sales tax added before or after the discount?
After, in most cases. The store takes the discount off first and then charges tax on the lower price, which is how this calculator works. That also means a discount saves you a little tax as well.
Is 50% off the same as buy one, get one free?
Only if you want two of the item. Buy one, get one free gives you two items for the price of one, which is 50% off each. If you only need one, a straight 50% off is the better deal.
How do I find the original price from a sale price?
Divide the sale price by the share you paid. If you paid $84 at 30% off, the original price was $84 ÷ 0.70 = $120.
Related calculators
- Discount Calculator — Final price after a percent or dollar discount, with an optional second stacked discount and sales tax.
- Sales Tax Calculator — Add sales tax to a price, take it back out of a total, or find the rate from a receipt.
- Percentage Calculator — Percent of a number, what percent one number is of another, percentage change and difference.
- Tip Calculator — Work out the tip and total on a bill, split it between several people, and round each share up if you like.
Results are estimates for educational purposes and are not financial, tax or legal advice. See our disclaimer.