This 3-in-1 percentage calculator answers the three most common percentage questions in one place. Enter Value A, Value B and a percentage to instantly get the result of applying that percentage to A, see what percent A is of B, and measure the percentage change from A to B. It is especially useful for grades, business reports, discounts, price changes, statistics and everyday math.
To find X% of a number A, multiply A by X and divide by 100. For example, 15% of 200 = 200 × 15 / 100 = 30.
Percentage change from A to B = ((B − A) / |A|) × 100. A positive result means an increase; negative means a decrease. Example: from 200 to 500 → ((500−200)/200) × 100 = 150% increase.
This tells you what proportion A represents relative to B, expressed as a percentage. Formula: (A / B) × 100. Example: 200 out of 500 = (200/500) × 100 = 40%.
Percentage change measures how a value increased or decreased relative to its starting point. Percentage difference usually compares two values symmetrically. This calculator focuses on percentage change from A to B.
Formulas: X% of A = (X/100) × A | A is what % of B = (A/B) × 100 | % change A→B = ((B−A)/|A|) × 100
Example: A = 200, B = 500, % = 15. → 15% of 200 = 30 | 200 is 40% of 500 | % change from 200 to 500 = +150%.
Most percentage searches fall into three groups: finding a percentage of a value, finding what percent one value is of another, and calculating percentage increase or decrease between two values. These look similar on the surface, but each one uses a different starting point and can produce the wrong answer if mixed up.
That is why a multi-purpose percentage calculator is useful. It reduces mistakes when moving between sales discounts, grade calculations, business reporting, margins, performance comparisons, and before-and-after price changes.
People often mix up percentage change and percentage difference, but they answer different questions. Percentage change compares a new value with an original value and is directional, so it tells you whether something went up or down from a starting point.
Percentage difference is more symmetric and is often used when comparing two values without treating one of them as the original reference. If your goal is to track change over time, percentage change is usually the right metric.
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