Percentage Change Calculator
Compute % change, % increase, % decrease, and % difference between two values - with the formula plugged in.
MATHFree percentage change calculator that computes % change, % increase, % decrease, and % difference between any two values. Shows the worked formula with your numbers substituted and displays all four methods side by side.
Enter an original value (V1) and a new value (V2), then pick a method. The calculator returns the percent result, the absolute difference, and the direction (rose, fell, or unchanged). It also shows all 4 methods at once so you can compare them. Worked example with V1=80, V2=100: % change = (100 − 80) ÷ 80 × 100 = +25%; % increase = 25% (since 100 > 80); % decrease = N/A (does not apply when V2 > V1); % difference = |100 − 80| ÷ ((80 + 100) ÷ 2) × 100 = 20 ÷ 90 × 100 ≈ 22.22%. Use % change for time-series data with a clear baseline, and % difference for unordered comparisons where neither value is a reference.
Percentage Change Calculator
Compute % change, % increase, % decrease, and % difference between any two values. Shows the worked formula with your numbers plugged in, plus all four methods side by side.
All Four Methods
Percentage Change vs Percentage Difference
Percentage change is a relative, directional measure: it compares a new value to an original baseline, so the denominator is V1 only. Percentage difference is symmetric and unsigned: the denominator is the average of V1 and V2, so swapping the two values gives the same answer. Change tells you "how much bigger or smaller did it get"; difference tells you "how far apart are they, treating neither as the baseline".
Use percentage change for time-series data where one value comes before the other - stock prices, salary raises, population growth, weight loss. Use percentage difference when the two values are unordered and you just want to express their gap, such as comparing two lab measurements, two products, or two regions. Percentage increase and percentage decrease are just the signed versions of percentage change: increase is only meaningful when V2 > V1, decrease when V2 < V1.
Two pitfalls catch most people. First, a 50% rise followed by a 50% fall does not return you to the start: 100 → 150 → 75. Second, the denominator matters. Going from 80 to 100 is a 25% increase, but going from 100 to 80 is a 20% decrease - same absolute gap, different percentages, because the baseline changed. Always be clear which value is V1.
Educational math utility.