What is X% of Y?
X is what percent of Y?
Percentage Change
Frequently Asked Questions
How do I calculate what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, to find what percent 30 is of 150: (30 ÷ 150) × 100 = 20%. This works for test scores, discounts, and any part-to-whole comparison.
What is the difference between percentage points and percent change?
Percentage points measure the absolute difference between two percentages (e.g., from 20% to 25% is a 5 percentage-point increase). Percent change measures the relative difference: (25 − 20) ÷ 20 × 100 = 25% increase. They answer different questions, so use the right one.
How do I reverse a percentage increase?
To reverse an X% increase, divide by (1 + X/100), not subtract X%. For example, if a $120 price reflects a 20% markup, the original was $120 ÷ 1.20 = $100. Subtracting 20% from $120 gives $96 — which is wrong.
Shahnawaz
Shahnawaz is the founder of DaProfitClub, a free online platform offering 100+ calculators and converters for finance, health, math, and everyday life. With a background in finance and mathematics, he designs accurate, easy-to-use tools.
Sources: Khan Academy — percentage word problems and percent change; NIST/SEMATECH e-Handbook of Statistical Methods — percentage calculations.