Percent off calculator
The sale price, what you save, and what the price was before.
Discount and sale price
off
Working: 80 × (1 − 25 ÷ 100) = 60
- You save
- 20
Stacked discounts
Each discount comes off the price left after the one before. Leave any you don't need empty.
with off, then off, then off
Working: 100 × (1 − 20 ÷ 100) × (1 − 10 ÷ 100) = 72
- You save
- 28
- Total discount
- 28%
Not 30%: each discount comes off the already-reduced price.
Original value before a percentage change
For questions like “the price after 20% off is 64, what was it?”. This divides; subtracting or adding the percentage gives the wrong answer.
After a , it's . What was it before?
Working: 64 ÷ (1 − 20 ÷ 100) = 80
- The decrease was
- 16
Not 76.8: the 20% was worked out on the original, not on 64.
Add or remove tax or VAT
Remove takes the tax out of a price that already includes it.
tax at on
Working: 100 × (1 + 20 ÷ 100) = 120
- Tax
- 20
- Before tax
- 100
Working out a sale price
Multiply the price by 1 minus the discount over 100. 25% off 80 is 80 × 0.75 = 60, so you save 20.
Two discounts don't add up
20% off and then another 10% off is 28% off, not 30%. The second discount comes off the price that's already been cut: 100 × 0.8 × 0.9 = 72. The order makes no difference.
Finding the original price
Divide the sale price by 1 minus the discount. If it's 64 after 20% off, it was 64 ÷ 0.8 = 80. Adding 20% to 64 gives 76.80, which is wrong.
Tax and VAT
To take 20% VAT out of a price of 120, divide by 1.2: the price before tax is 100 and the tax is 20. Taking 20% of 120 would give 24, which is too much.
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