Percentage Calculator
Calculate percentages three ways: what is X% of Y, X is what percent of Y, and percentage change between two values. Fast and simple.
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About This Tool
Percentage calculations appear constantly in everyday life — discounts, tax, growth rates, tip amounts, and test scores all involve percentages. Despite being mathematically simple, it's easy to confuse the three common percentage questions. QuickKit's Percentage Calculator provides three clearly labeled modes, each handling a distinct type of percentage problem, so you always pick the right formula without second-guessing.
Features
- ✓Three Calculation Modes — Mode 1: X% of Y. Mode 2: what % is X of Y. Mode 3: % change from X to Y. Three distinct problems, one tool.
- ✓Instant Results — Results update as you type in any field — no need to press Calculate.
- ✓Percentage Change Direction — Mode 3 correctly shows positive values for increases and negative values for decreases.
- ✓Clean Numeric Output — Results are rounded to two decimal places for readability, avoiding floating-point noise.
- ✓No Login Required — Fully client-side calculation — works offline and requires no account or data submission.
FAQ
- How do I calculate X% of a number?
- To find X% of Y: multiply Y by X and divide by 100. For example, 15% of 200 = (200 × 15) / 100 = 30. Use Mode 1 in this tool. Common uses: calculating a 20% tip, finding 30% off a price, or working out VAT on a total.
- How do I find what percentage one number is of another?
- To find what percentage X is of Y: divide X by Y and multiply by 100. For example, 45 is what % of 180? = (45 / 180) × 100 = 25%. Use Mode 2. Common uses: exam score percentages, market share calculations, completion ratios.
- How do I calculate percentage change?
- Percentage change from X to Y = ((Y − X) / |X|) × 100. A positive result is an increase; a negative result is a decrease. For example, from 80 to 100 = ((100 − 80) / 80) × 100 = +25%. Use Mode 3. Common uses: year-over-year growth, price changes, weight loss/gain.
- Why does Mode 3 use the absolute value of the original number?
- Dividing by the absolute value of the original ensures correct behavior when the starting value is negative (e.g. a loss turning into a gain). If the original were negative and you divided by the raw value, the sign of the result would flip unexpectedly. Using |X| in the denominator keeps the percentage change direction consistent with the actual movement.