How is percentage increase or decrease calculated?

Percentage change = (new value − old value) ÷ old value × 100. A positive result is an increase, a negative result is a decrease. Applying a p% change to a value V gives V × (1 + p/100).

How accurate are the results?

Calculations use standard IEEE-754 double-precision arithmetic and are rounded to six decimal places for display. They are exact for everyday financial and statistical use; percentage change is undefined when the original value is 0.

Is my data sent anywhere?

No. The calculator is privacy-first — every figure stays in your browser and nothing is transmitted to any server.

Percentage Increase / Decrease Calculator

Find the % change between two numbers, or apply a % rise or fall.

Percentage increase / decrease calculator

Quickly find the percentage change between two numbers, or apply a percentage rise or fall to any value. Enter a negative percentage to model a decrease.

It is privacy-first: all arithmetic happens locally in your browser, so the numbers you enter never leave your device.