Reverse Percentage Calculator
Know the final price after a discount or increase — but want the original? Enter the result and the percentage, get the starting number.
How Reverse Percentage Works
If a value was increased by X%, divide the final value by (1 + X/100):
If a value was decreased by X%, divide the final value by (1 − X/100):
Real-World Examples
Price after discount: A jacket costs £91 after a 30% sale. Original price = 91 ÷ (1 − 0.30) = 91 ÷ 0.70 = £130.
Price after tax: A product costs $113 after 13% tax. Pre-tax price = 113 ÷ 1.13 = $100.
Salary after raise: You earn $57,500 after a 15% raise. Previous salary = 57,500 ÷ 1.15 = $50,000.
Common Mistake
A lot of people try to reverse a 20% increase by subtracting 20% from the result. That's wrong. If something increased 20% from £100 to £120, subtracting 20% of £120 gives £96 — not £100. You must divide, not subtract.
Common Questions
What is the original price if £91 is after a 30% discount?
91 ÷ (1 − 0.30) = 91 ÷ 0.70 = £130. Always divide — never subtract the percentage from the final value.
How do I find the pre-VAT price?
If the VAT rate is 20%, divide the VAT-inclusive price by 1.20. For example, £120 including 20% VAT → £120 ÷ 1.20 = £100 ex-VAT.
What's the original value if £80 is after a 20% increase?
80 ÷ 1.20 = £66.67. The original value was £66.67 before the 20% increase was applied.