| Original value | $0.00 |
| Final value | $0.00 |
| Difference | $0.00 |
| Percentage change | 0% |
How to use this calculator
Enter the final amount you already know — the sale price, the new price, or the reduced figure. Select whether that value was the result of a decrease (like a discount) or an increase (like a markup). Enter the percentage. Hit calculate and you'll see the original starting value immediately.
How to find the original price before a discount
- Take the sale price (e.g. $85)
- Subtract the discount percentage from 100 (e.g. 100 - 15 = 85)
- Divide that by 100 to get a decimal (e.g. 0.85)
- Divide the sale price by that decimal (e.g. $85 / 0.85 = $100)
The original price was $100. The 15% discount saved you $15. The calculator above does this in one step — just enter the numbers and it handles the formula.
Common uses for reverse percentage
Shopping is the most common scenario. You see an item for $60 in a 25% off sale and want to know whether the "original" price was realistic or inflated. Divide $60 by 0.75 and you get $80 — the supposed original. If you've seen that item listed at $80 before, the deal is genuine. If not, it might be a manufactured discount.
The same logic works for salary negotiations. If a job listing says the role pays 20% more than your current salary, you can work backwards to verify the numbers add up. It also works for VAT and GST — if you know the tax-inclusive price, find the pre-tax amount by reversing the tax rate.