Percentage Change Calculator

Enter a previous and current value to calculate the rate of increase or decrease.

Category: Calculators

When to use?

Use it to calculate the ratio of change between two points in time, such as month-over-month sales growth, stock returns, or population change. A positive result means an increase, a negative one a decrease.

How to use

  • Enter the previous value (baseline).
  • Enter the current value.
  • The rate of change (%) is calculated automatically.

Input Explanation

Enter the baseline value before the change and the comparison value after it.

Calculation Basis

Rate of change = (current − previous) ÷ |previous| × 100. Positive means increase, negative means decrease.

Usage Examples

  • Check sales growth - Calculate the percentage increase in sales versus the previous month.
  • Calculate stock returns - Find the return from a buy price and the current price.
  • Analyze trends - Compute the change rate between two figures to spot a trend.

Examples

  • Previous 1,000,000 → current 1,200,000: +20%
  • Previous 200 → current 150: −25%

Cautions

  • The rate of change cannot be calculated when the baseline value is 0.
  • If the baseline is negative or close to 0, the rate may appear abnormally high or fail to calculate.

Guides

Rate of change formula

Rate of change = (after − before) ÷ before × 100. Positive means an increase, negative a decrease.

Do not confuse with percentage points

Going from 20% to 25% is a rate of change of (25−20)/20×100 = 25%, while a 5 percentage-point increase is the plain difference.

FAQ

What is the formula?

(current − previous) ÷ |previous| × 100.

What if the previous value is negative?

It calculates using the absolute value and shows direction by sign.

How are increase and decrease distinguished?

A positive result means increase; a negative result means decrease.

Can it calculate when the previous value is 0?

No — you cannot divide by zero, so a baseline of 0 has no result.

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