Reverse Percentage Calculator
Solve "X is Y%, what is the total?" math problems to find the original 100% value.
Reverse Percentage
If X is Y%, what is 100%?
How to Calculate Reverse Percentages
Reverse percentage calculations allow you to work backward from a known percentage and its value to find the original 100% total value. This is highly useful for finding prices before sales tax (VAT/GST) or original prices before discount promotions.
The Reverse Percentage Formula
Original Value = (Part / Percentage) × 100
Step-by-Step Calculation
- Identify the partial value (the part) and the percentage it represents.
- Divide the part by the percentage rate.
- Multiply the resulting number by 100 to get the original 100% total.
For example, if you know that $25 is 20% of a total price: divide 25 by 20 to get 1.25. Multiply by 100 to find the original total price of $125.
Frequently Asked Questions
If a product costs $120 including 20% tax, the pre-tax price is calculated by dividing the total price by 1.20 (which is 1 + 20/100). So, $120 / 1.20 = $100.
The formula is (Part / Percentage) × 100.
To find the original price before a discount, divide the sale price by 1 minus the discount rate (in decimal form). For example, if a jacket costs $80 after a 20% discount, divide $80 by 0.80 (1 - 0.20) to get the original price of $100.