Percentage Calculator
Solve common percent problems: percent of a number, percent change, and what percent one number is of another. It’s useful for discounts, growth rates, test scores, and quick everyday math.
Inputs
%
Result
30
Formula: (percent / 100) × number
How to use it
- Choose the type of percent question (tabs).
- Enter the values you know.
- The calculator computes the missing value instantly.
- Use the explanation to double-check the logic.
Key formulas
- Percent of
- X% of Y = (X/100) × Y
- What percent
- X is what % of Y = (X/Y) × 100
- Percent change
- Percent change = ((New − Old) / Old) × 100
FAQ
Percent change is ((new − old) ÷ old) × 100. If the result is positive, it’s an increase; if negative, it’s a decrease.
Use (X ÷ Y) × 100. For example, 25 is what percent of 200? → (25/200)×100 = 12.5%.
Percent of computes a portion of a number. Percent change compares how much something increased/decreased relative to the starting value.
Percent change isn’t defined when the starting value is 0. Use an absolute difference instead.
Percent is relative (e.g. 10%). Percentage points are an absolute difference between percentages (e.g. 5% to 7% is +2 percentage points).
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Disclaimer
Results are calculated from the numbers you enter. Double-check inputs and rounding for important decisions.