Percentage change asks how far a quantity moved relative to where it started. The standard answer is ((new − original) ÷ original) × 100. If a price goes from 80 to 100, the change is +25%. If it falls from 100 to 80, the change is −20%. Those two figures are not mirrors of each other, because the base changed. A percentage change calculator that hides the base invites the common “it went up 25% and back 25% so we are even” mistake.
This page has two fields only: original value and new value. The result names the direction (increase, decrease, or unchanged), the percentage, and the absolute difference. That is the whole job. It does not ask “what is 15% of 80.” For that, use the Percentage Calculator.
The original value must not be zero. Dividing by zero is not a large percentage; it is undefined. The status says so. Negative originals are accepted and documented: the algebra is the usual one, and the words “increase” and “decrease” follow the sign of (new − original), not a finance convention about losses.
Leave a field empty and the status asks for that number. Text that is not a number is rejected. The result box stays hidden until a valid pair is entered, so a previous answer cannot linger next to a failed attempt.
percentage change = ((new − original) ÷ original) × 100. Absolute change = new − original. Direction is increase when the absolute change is positive, decrease when it is negative, and unchanged when it is zero. There is no special case for “percent more than” wording. If someone says “B is 25% more than A,” that is a different sentence from “A changed by 25% to reach B,” though the numbers often match when A is the original.
Original 80, new 100: direction Increase, percentage 25%, absolute change 20. Original 100, new 80: Decrease, −20%, absolute change −20. Original 50, new 50: Unchanged, 0%, absolute change 0. Original 0, new 10: no percentage. The status explains that the formula divides by the original value.
(100 − 80) / 80 × 100 = 25%
(80 − 100) / 100 × 100 = −20%People also ask for “percent difference,” which is a different formula: the absolute gap divided by the average of the two values. This page does not compute that. Percent difference is symmetric; percentage change is not. If a report mixes the two names, check which base they used before you trust the figure.
If you also need “what percent is 12 of 60,” go back to the Percentage Calculator. That page keeps all three school questions. This one stays on the change between two amounts. Neither page is a compound-growth or investment-return calculator.
Formula: ((new − original) ÷ original) × 100. An original value of 0 cannot produce a percentage.
((new − original) ÷ original) × 100. The original value is the base.
The percentage is undefined. The tool reports that instead of Infinity.
The same formula runs. A move from −20 to −10 is a 50% increase toward zero. That is algebraically correct and easy to misread in prose, so check the sign of the base.
That page also answers “what is X% of Y” and “X is what percent of Y.” This page is only original versus new, with direction labels.
