How to Calculate a Discount (Percent Off)

A discount is just a percentage taken off the original price. There are two things you might want: the amount you save, or the price you actually pay. For the saving, multiply the price by the percent off. For the final price, multiply by what's left after the discount. The discount calculator gives you both at once, but the mental math is quick once you see it.

The two ways to calculate it

To find the saving: price × (percent off ÷ 100). A 30% discount on a $60 jacket is 60 × 0.30 = $18 off.

To find the final price: subtract the saving, or take a shortcut — multiply by (1 − the rate). At 30% off you keep 70%, so 60 × 0.70 = $42 in one step. The shortcut is faster because it skips the subtraction.

Doing it in your head

Round percentages have easy anchors. 10% is the price with the decimal moved one place left ($60 → $6), so 30% is three of those ($18). 50% is just half. 25% is half of a half. Most real discounts are built from these: 40% off is 10% four times, or half minus 10%. Once you can find 10% instantly, the rest falls out.

Watch the order with tax and stacked discounts

Two things trip people up at the register. First, tax goes on after the discount, on the reduced price — so calculate the sale price first, then add tax with the sales tax calculator. Second, "an extra 20% off an already 30%-off item" is not 50% off. You take 30% off, then 20% off that smaller price — which works out to 44% off the original, not 50%. Stacked discounts always multiply; they never simply add.

Worked example

A $120 pair of shoes at 25% off, with 8% sales tax:

• Discount: 120 × 0.25 = $30 off
• Sale price: 120 − 30 = $90 (or 120 × 0.75)
• Tax: 90 × 0.08 = $7.20
• Total: $97.20

The percentage move here is the same one behind everything in our percentage and everyday math calculators — if the base idea feels shaky, how to calculate a percentage walks through it. The percentage calculator handles any "percent of a number" step directly.

Frequently asked questions

How do I calculate a percentage discount?

Multiply the original price by the percent off (as a decimal) to get the saving. For the final price, multiply by 1 minus that decimal — a 30% discount means multiplying by 0.70.

What's the fastest way to find a sale price?

Multiply the price by what you keep, not what you save. At 30% off you keep 70%, so × 0.70 gives the final price in one step, no subtraction needed.

Is 30% off plus an extra 20% off the same as 50% off?

No. The second discount applies to the already-reduced price. 30% then 20% is 0.70 × 0.80 = 0.56, so you pay 56% — a 44% discount, not 50%.

Do I add tax before or after the discount?

After. Sales tax is charged on the discounted price, so calculate the sale price first, then apply tax to that lower amount.

How do I calculate 40% off in my head?

Find 10% (move the decimal one place left) and multiply by 4 for the saving, or take half the price and add back 10%. On $50: 10% is $5, so 40% off is $20 saved, leaving $30.