Percentage Change Calculator
Two modes: find the exact percentage change between any two values (increase or decrease), or apply a known percentage change to calculate the resulting value. Used for tracking price changes, growth rates, discounts, and performance metrics.
Formula
Percentage Change = ((New − Old) ÷ |Old|) × 100 New Value = Old Value × (1 + Change% ÷ 100)
To find the percentage change, subtract the old value from the new, divide by the absolute value of the old, and multiply by 100. A positive result means increase; negative means decrease. To apply a change, multiply the original value by (1 + rate).
Worked Examples
Frequently Asked Questions
What is the formula for percentage change?▾
Percentage change = ((New Value − Old Value) ÷ |Old Value|) × 100. A positive result means the value increased; a negative result means it decreased. Always divide by the original (old) value, not the new one.
How do I calculate a percentage increase?▾
Subtract the original value from the new value, divide by the original, and multiply by 100. For example, from 80 to 100: (100 − 80) ÷ 80 × 100 = 25% increase.
How do I calculate a percentage decrease?▾
Same formula as percentage increase — the result will simply be negative. For example, from 100 to 75: (75 − 100) ÷ 100 × 100 = −25% (a 25% decrease).
What is the difference between percentage change and percentage points?▾
Percentage change is relative: from 20% to 25% is a 25% change ((25−20)÷20×100). Percentage points measure the absolute difference: 25% − 20% = 5 percentage points. These are very different and often confused.
How do I reverse a percentage change to find the original value?▾
If you know the current value and the percentage change, divide by (1 + change/100). For example, a value is now $120 after a 20% increase: $120 ÷ 1.20 = $100 original. Use the Remove VAT or Reverse Percentage calculator for this.
How is percentage change different from ROI?▾
ROI (Return on Investment) uses the same percentage change formula but is specifically applied to financial returns: (Gain − Investment) ÷ Investment × 100. Percentage change is the general-purpose version of that same calculation.
Related Calculators
All calculations are for informational purposes only. They should not replace professional financial, tax, or legal advice. Always consult a qualified professional for decisions affecting your finances or business.