Calculate percentage increase or decrease between two values for price changes, growth rates, and performance metrics.
Subtract the original value from the new value.
Divide the difference by the absolute original value.
Convert to a percentage by multiplying by 100.
Cross-checked against authoritative formulas (IRS, NIST, ACM) and updated for 2025/2026 tax years and rates.
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Estimates only. Calculator results are for educational and planning purposes — not professional advice. For binding decisions on taxes, investments, health, or legal matters, consult a qualified professional.
FAQ
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A percentage change calculator is a free math tool that finds the percentage increase or decrease between two values. Our percentage change calculator uses the formula ((new - old) / old) x 100 and shows the absolute change too. The percentage change calculator is used for stock returns, price changes, growth rates, and performance metrics.
How it works
Our percentage change calculator lets you find the percentage increase or decrease between any two numbers, in three steps.
Type the starting value - this is the baseline the percentage is calculated from. For year-over-year changes, this is last year's number.
Type the ending value. For year-over-year, this is the current year's number. The calculator uses the original as the denominator.
The result shows the absolute change and the percentage change. The sign indicates increase or decrease, and the magnitude is the strength of the change.