How to Calculate the Discount Percentage Between Two Prices
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You see an item on sale and you want to know what percent off it is — but the tag only shows the old price and the new price, not the discount. This is the reverse of the standard discount calculation, and the math is straightforward.
The Formula
Discount Percentage = ((Original Price - Sale Price) ÷ Original Price) × 100
Three steps:
- Subtract the sale price from the original price (this gives you the savings amount)
- Divide the savings by the original price (this gives you the discount as a decimal)
- Multiply by 100 to express as a percentage
Example: Original $80, sale $60.
- Savings = $80 - $60 = $20
- Decimal = $20 ÷ $80 = 0.25
- Percentage = 0.25 × 100 = 25%
So $60 from $80 is a 25% discount.
Why You Divide by Original, Not Sale
A common mistake is dividing the savings by the sale price instead of the original. This produces a different (and bigger) percentage that does not match how stores describe discounts.
Wrong way: $20 ÷ $60 = 33% (this is the markup from sale to original, not the discount)
Right way: $20 ÷ $80 = 25% (this is the actual discount percentage)
The rule: divide by the bigger number (the original price), not the smaller number. Discounts are always expressed as a percentage of the original price.
Sell Custom Apparel — We Handle Printing & Free ShippingWorked Examples
| Original | Sale | Savings | Discount % |
|---|---|---|---|
| $50 | $45 | $5 | 10% |
| $100 | $85 | $15 | 15% |
| $80 | $64 | $16 | 20% |
| $200 | $150 | $50 | 25% |
| $60 | $42 | $18 | 30% |
| $150 | $90 | $60 | 40% |
| $75 | $37.50 | $37.50 | 50% |
| $300 | $120 | $180 | 60% |
| $50 | $15 | $35 | 70% |
When You Need This Calculation
Three common situations:
Comparing two sales. Store A has an item for $79 (was $99). Store B has the same item for $69 (was $89). Which is the better discount? Store A is 20.2% off; Store B is 22.5% off. Same dollar savings ($20), but Store B is a slightly bigger percentage off the original.
Verifying a "70% off" claim. A store says "70% off" but you suspect they raised the prices first. Calculate the actual discount: if the original was $40 and the sale price is $29, that is only 27.5% off, not 70%. The store is bending the truth.
Reporting your savings. You bought something on sale and want to tell your friend "I got it for X% off." Use this formula to figure out the percentage from the prices you actually paid.
free discount calculator can do this calculation directly — enter the original and sale prices and it shows you the percentage discount that was applied.
Find the Discount Percentage
Enter original and sale price — see the percent off in seconds.
Open Discount CalculatorFrequently Asked Questions
What if my numbers come out as a long decimal?
Round to one or two decimal places for readability. "23.45% off" is fine; "23.4567891% off" is overkill. For shopping, one decimal is enough. For accounting, two decimals is standard.
Does the formula work for percentage increases?
Yes, but the result will be a markup percentage instead of a discount. If the new price is higher than the old price, the formula gives you a positive number representing the price increase as a percentage of the original.
Can I do this calculation in Excel?
Yes. The formula is =(A1-B1)/A1 where A1 is the original price and B1 is the sale price. Format the cell as percentage and Excel will display the result correctly.