Reverse Percentage Calculator

How to Reverse a Percentage

Sometimes you know the final price after a percentage was added (like tax or a markup) and need to work backwards to find the original amount. This is called a reverse percentage calculation. Instead of multiplying, you divide — undoing the percentage that was applied.

The Formula: Original = Final Value ÷ (1 + Percentage ÷ 100)

For decreases, use a negative percentage. If a price dropped 25% to land at $75, enter 75 and −25 to find the original was $100.

Real-World Uses

• Tax-inclusive pricing: A receipt shows $59.99 including 8% sales tax. The pre-tax price is $59.99 ÷ 1.08 = $55.55. For VAT-specific calculations, use our VAT Calculator.
• Salary after raise: Your new salary is $68,000 after a 6% raise. Your previous salary: $68,000 ÷ 1.06 = $64,150.94.
• Investment returns: A portfolio is now worth $13,200 after a 10% gain. The starting value: $13,200 ÷ 1.10 = $12,000.
• Deflated prices: A house is listed at $380,000 after a 5% decline. Original value: $380,000 ÷ 0.95 = $400,000.

Why Simple Subtraction Doesn't Work

A common mistake is subtracting the percentage from the final value directly. If $120 includes a 20% increase, subtracting 20% of $120 ($24) gives $96 — not the correct $100. The percentage was applied to the original value, not the final one. This calculator handles the math correctly every time.

To calculate the forward direction — applying a percentage increase — use our Percentage Increase Calculator. For a broader foundation, read How to Calculate a Percentage.

Common Reverse Percentage Examples

Working backwards from a known final value. Click any row to load the values in the calculator.