Percentage Calculator
Find percentages, percentage change, and percentage of totals.
What is X% of Y?
X is what percent of Y?
Percentage change from X to Y
X increased / decreased by Y%
Discount — What % off?
Frequently Asked Questions
How do I calculate a percentage of a number?
Multiply the number by the percentage divided by 100. Formula: Result = Number × (Percentage ÷ 100). Example: 30% of 250 = 250 × 0.30 = 75. This is the most common percentage calculation — used for tips, tax, discounts, and commissions.
How do I calculate percentage increase or decrease?
Percentage change = ((New Value − Old Value) ÷ Old Value) × 100. Positive result = increase; negative = decrease. Example: price goes from $80 to $100: ((100 − 80) ÷ 80) × 100 = 25% increase. If it drops from $100 to $80: ((80 − 100) ÷ 100) × 100 = −20% decrease.
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100. Formula: % = (Part ÷ Whole) × 100. Example: 45 out of 180 questions correct = (45 ÷ 180) × 100 = 25%. This works for test scores, completion rates, market share, and many other ratios.
How do I calculate the original number before a percentage increase?
Divide the final number by (1 + percentage as decimal). Example: a price is now $120 after a 20% increase — original = $120 ÷ 1.20 = $100. For a decrease: divide by (1 − percentage). Example: $80 after a 20% decrease — original = $80 ÷ 0.80 = $100.
What is the difference between percentage points and percent?
Percentage points are the arithmetic difference between two percentages. If interest rates rise from 3% to 5%, that's a 2 percentage point increase — but it's a 66.7% increase in the rate itself. This distinction matters in financial reporting and policy discussions.