- What does percentage change measure?
- It compares a new value to an original value using (new - original) ÷ |original| × 100. A negative result is reported as a decrease.
- Why is division by zero rejected?
- Percent-of-a-number and percentage-change calculations are undefined when the denominator is zero, so the tool reports this explicitly.
- How many decimals are shown?
- Up to six decimal places; trailing zeros are dropped. Internally the calculation uses full precision.