Percent off chart and how to calculate a discount
A discount of P% means you pay (100 − P)% of the price. Sale price = price × (1 − P ÷ 100). The charts below give the sale price for the most common discounts, then the guide explains double discounts, finding the percent off from two prices and a few tricks for doing it in your head at the till.
Percent off chart
Each cell is the price you pay after the discount in the left column.
| Discount | $20 | $50 | $100 | $250 | $500 |
|---|---|---|---|---|---|
| 5% | $19.00 | $47.50 | $95.00 | $237.50 | $475.00 |
| 10% | $18.00 | $45.00 | $90.00 | $225.00 | $450.00 |
| 15% | $17.00 | $42.50 | $85.00 | $212.50 | $425.00 |
| 20% | $16.00 | $40.00 | $80.00 | $200.00 | $400.00 |
| 25% | $15.00 | $37.50 | $75.00 | $187.50 | $375.00 |
| 30% | $14.00 | $35.00 | $70.00 | $175.00 | $350.00 |
| 33% | $13.40 | $33.50 | $67.00 | $167.50 | $335.00 |
| 40% | $12.00 | $30.00 | $60.00 | $150.00 | $300.00 |
| 50% | $10.00 | $25.00 | $50.00 | $125.00 | $250.00 |
| 60% | $8.00 | $20.00 | $40.00 | $100.00 | $200.00 |
| 70% | $6.00 | $15.00 | $30.00 | $75.00 | $150.00 |
| 75% | $5.00 | $12.50 | $25.00 | $62.50 | $125.00 |
| 80% | $4.00 | $10.00 | $20.00 | $50.00 | $100.00 |
| 90% | $2.00 | $5.00 | $10.00 | $25.00 | $50.00 |
- Original price
- 80
- You save
- − 20
- Price after discount
- 60
80 − 80 × 25 ÷ 100 = 60
Discount from two prices
(120 − 90) ÷ 120 × 100 = 25
25%
How to work out a discount in your head
- 10% off: take one tenth off. $64 → $57.60.
- 20% off: take off twice 10%. $64 → $51.20.
- 25% off: take off a quarter. $64 → $48.00.
- 30% off: three times 10%. $64 → $44.80.
- 15% off: 10% plus half of it. $64 → $54.40.
- Pay-percentage method: 35% off means you pay 65%. $80 × 0.65 = $52.00.
Double discounts: "an extra 20% off"
When a store adds a second discount to a sale price, the second percentage is taken from the already reduced price. 30% off and then an extra 20% off is not 50% off; it is 1 − 0.7 × 0.8 = 44% off. On a $100 item that is $56.00 instead of $50.
| First discount | Extra discount | Total off | Not |
|---|---|---|---|
| 10% | 10% | 19% | 20% |
| 20% | 10% | 28% | 30% |
| 25% | 10% | 32.5% | 35% |
| 30% | 20% | 44% | 50% |
| 40% | 20% | 52% | 60% |
| 50% | 20% | 60% | 70% |
| 50% | 50% | 75% | 100% |
| 60% | 30% | 72% | 90% |
The order of the two discounts does not matter: 20% then 30% gives the same total as 30% then 20%. What matters is that they multiply.
Finding the percent off from two prices
If a jacket was $120 and is now $90, the discount is (120 − 90) ÷ 120 × 100 = 25%. Always divide by the original price. If you divide by the sale price you get 33.33%, which overstates the deal.
Discounts and sales tax
In the US, sales tax is added to the discounted price. A $80 item at 25% off with 8% sales tax: $80 → $60.00 → $64.80. Mathematically the order does not change the total (multiplication again), but the receipt shows the discount first. In the UK and the EU, shelf prices already include VAT, so a discount comes off the VAT-inclusive price — see the VAT calculator.
"Buy one get one" in percentages
- Buy one, get one free = 50% off each item when you buy two.
- Buy one, get one half price = 25% off the pair: you pay 1.5 items for 2.
- 3 for 2 = 33.33% off when you buy three.
- Spend $100, save $20 = 20% off if you spend exactly $100, less if you spend more.
Is a bigger percentage always a better deal?
Not necessarily. 40% off a $150 price that was raised the week before may cost more than 20% off the usual $100 ($90.00 vs $80.00). Compare the final prices, not the percentages. Price-history sites and the percentage increase calculator help you check how much a price moved before the sale.
Working backwards: the price before the discount
Sometimes you only know what you paid. If you paid $63.00 after 30% off, the original price was 63 ÷ 0.7 = $90.00. The rule is: divide the sale price by the share you paid (100% minus the discount). Adding 30% back to $63.00 gives $81.90, which is wrong for the same reason that undoing any percentage change needs a division, not a subtraction.
Coupons, cash back and loyalty points
A fixed-amount coupon is a different percentage depending on the price: $10 off a $40 order is 25%, but $10 off $200 is only 5%. Cash back and points work the same way. When a deal combines a percentage with a fixed amount, the order matters: 20% off $100 then $10 off gives $70.00, while $10 off first and then 20% off gives $72.00. Stores usually apply the percentage first, which is slightly better for them.
Discounts for businesses
If you sell things, a discount comes straight out of your margin. With a 40% margin, a 20% discount removes half of the profit on each item: a product costing $60 and selling at $100 earns $40, but at $80.00 it earns only $20. The margin calculator shows the numbers for your own prices.
Quick reference: what you pay
- 10% off → pay 90% (× 0.9)
- 15% off → pay 85% (× 0.85)
- 20% off → pay 80% (× 0.8)
- 25% off → pay 75% (× 0.75)
- 30% off → pay 70% (× 0.7)
- 40% off → pay 60% (× 0.6)
- 50% off → pay half (× 0.5)
- 75% off → pay a quarter (× 0.25)
Percent off in a spreadsheet
With the price in A2 and the discount in B2 (typed as 25%), the sale price is =A2*(1-B2) and the saving is =A2*B2. For two stacked discounts in B2 and C2, use =A2*(1-B2)*(1-C2). To find the discount from two prices, use =(A2-B2)/A2 with the original price in A2 and the sale price in B2, formatted as a percentage.
Rounding at the till
Shops round each sale price to the cent, usually to the nearest cent, so a basket of discounted items can differ by a cent or two from a discount taken on the basket total. For example, 15% off three items at $9.99 is $8.49 each, while 15% off the total of $29.97 is $25.47. Both are correct; they just round at different moments.
Sale signs worth reading twice
- "Up to 70% off" means some items have 70% off and most have less.
- "Was $80, now $56" is 30% off — divide the saving by the old price to check the sign.
- "Extra 20% off sale prices" stacks on the sale price, not on the original.
- "Save $30 when you spend $150" is 20% only at exactly $150.
Summary
Multiply the price by the share you pay, never add discounts together, divide by the original price to find the percent off, and divide by the share you paid to get back to the original price. Compare final prices rather than percentages, and check whether a second discount applies to the original or the already reduced price.
Frequently asked questions
How do I calculate the sale price?
Multiply the price by (1 − discount ÷ 100). 30% off $70 = 70 × 0.7 = $49.
What is 20% off $50?
$40.00 — you save $10.00.
Is 20% + 20% the same as 40% off?
No, it is 36% off.
How do I calculate the original price before a discount?
Divide the sale price by (1 − discount ÷ 100). $60 after 25% off was 60 ÷ 0.75 = $80.00.