Math & EverydayVerified: 2026-10-05
Percentage Calculator
Calculate percentages, percentage increase and decrease, percentage difference, and what percent one number is of another with step-by-step mathematical breakdowns.
Direct Answer:To find what is X% of Y, multiply X by Y and divide by 100 (e.g., 10% of 500 = 50). To find what percent X is of Y, divide X by Y and multiply by 100 (e.g., 50 is 25% of 200). For percentage increase from X to Y, compute ((Y - X) / X) × 100 (e.g., 100 to 120 = +20%).
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Adjust Parameters
Formula Mode:What is X% of Y?
%
%
Calculated Answer
50
10% of 500 is 50
Original Base (Y)
500
Base + 10%
550
Value after percentage addition
Base − 10%
450
Value after percentage discount/subtraction
Step-by-Step Mathematical Work
- Step 1: Convert percentage to decimal: 10 ÷ 100 = 0.1000
- Step 2: Multiply by base value: 0.1000 × 500 = 50
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How Percentage Calculator is Calculated
Transparent mathematical formulas and assumptions used across our financial engines.
Mathematical Formula
\text{Percentage Value} = \frac{X}{100} \times Y \quad | \quad \text{Rate (\%)} = \frac{X}{Y} \times 100
Variables & Legend
X
Percentage or First Number
Y
Base or Second Number
Step-by-Step Calculation
- Percent of Value:
(X / 100) * YMultiplies the decimal fraction by the total base quantity.
- Fraction to Percent:
(X / Y) * 100Expresses part X as a proportion out of 100 against whole Y.
- Percentage Change:
((Y - X) / X) * 100Calculates proportional growth or reduction relative to initial base X.
Conventions & Assumptions
- Percentages represent hundredths: 1% = 0.01.
- Division by zero is undefined; base values (Y) cannot be zero when finding rates.
Frequently Asked Questions
Divide the part (X) by the total (Y), then multiply the resulting decimal by 100. For example, to find what percentage 25 is of 200: (25 ÷ 200) × 100 = 0.125 × 100 = 12.5%.