CalcWhenPercentage Change Calculator
Going from 80 to 100 is a +25% increase — and going back from 100 to 80 is a 20% decrease, because the same 20 rides on a different base.
How it works
Enter where something started and where it ended — a price, a salary, a follower count, a temperature of business — and read the change as a percentage, signed and labelled increase or decrease. The multiplier is shown too (×1.25), because multiplying is how the change is actually applied next time.
This is the tool that makes headlines honest: a rise from 2% to 3% is +1 percentage point but a +50% change, and the panel's plain figures let you say which you mean.
The method
Change = (new − old) ÷ |old| × 100. The absolute value in the divisor keeps the sign meaningful when the starting value is negative (a loss narrowing from −50 to −25 reads as a 50% improvement in the value, and the panel shows the raw change beside it for audit).
Frequently asked questions
What is the difference between percent and percentage points?
Points are the plain subtraction of two percentages (3% − 2% = 1 point). Percent change is relative (that same move is +50%). News reports blur them constantly; this calculator reports the relative figure and shows both raw values.
Why is +25% followed by −25% not back to start?
Bases again: 100 up 25% is 125; 125 down 25% is 93.75. Equal percentages on different bases are different amounts of stuff.
Can the starting value be zero?
No honest answer exists — any move from zero is infinitely large in percentage terms — so the tool says so instead of printing infinity.