BCBetter Calculators

Percentage Calculator

Calculate percentages, percentage change, and what percentage one number is of another.

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Enter your values and click Calculate

How It Works

This calculator handles three distinct percentage operations, each using its own formula. Mode 1 — 'What is X% of Y?': Result = (X ÷ 100) × Y. This finds a fractional portion of a number. For example, 15% of 200 = (15 ÷ 100) × 200 = 0.15 × 200 = 30. Use this for tips, tax amounts, discounts, and commission figures. Mode 2 — 'X is what % of Y?': Result = (X ÷ Y) × 100. This expresses X as a proportion of Y scaled to a 0–100 range. For example, 45 is what % of 180 = (45 ÷ 180) × 100 = 25%. Use this for test scores, completion rates, and market share calculations. Mode 3 — 'Percentage change from X to Y': Result = ((Y − X) ÷ |X|) × 100. This measures the relative change between a starting and ending value. The formula uses the absolute value of X in the denominator so it behaves correctly even when the starting value is negative. A positive result is an increase; a negative result is a decrease. For example, from 80 to 100: ((100 − 80) ÷ 80) × 100 = 25% increase. The absolute difference between X and Y is displayed alongside the percentage so you have both the relative and absolute context.

Examples

What is 15% of 200?
Finding a percentage of a number — the most common use case for tips, taxes, and discounts.
Result: 15% of 200 = 30.
45 is what percent of 180?
Expressing one number as a percentage of another — useful for test scores, task completion, and market share.
Result: 45 is 25% of 180.
Percentage change from 80 to 100
Calculating the relative increase between two values — used in financial returns, growth reports, and scientific measurements.
Result: 25% increase. Absolute difference: 20.

Frequently Asked Questions

How do I calculate a percentage increase?
Subtract the starting value from the ending value, divide the result by the starting value, then multiply by 100. The formula is: ((New − Old) ÷ Old) × 100. For example, a change from 80 to 100 = ((100 − 80) ÷ 80) × 100 = 25% increase. A negative result means a decrease rather than an increase.
What does per cent mean?
The word percent comes from the Latin 'per centum', meaning 'by the hundred'. A percentage is a ratio expressed as a fraction of 100 — so 25% means 25 out of every 100, or 0.25 as a decimal. Multiplying any decimal by 100 converts it to a percentage; dividing any percentage by 100 converts it back to a decimal.
What is the difference between percentage points and percent change?
Percentage points measure the arithmetic difference between two percentages. If an interest rate rises from 3% to 5%, it has increased by 2 percentage points. Percent change measures the relative increase: ((5 − 3) ÷ 3) × 100 = 66.7%. These two metrics are frequently confused in news reporting and financial analysis — a politician who says taxes increased 'by 2%' almost always means 2 percentage points, not a 2% relative change on the previous rate.

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