About the Percentage Calculator
Calculate Percentages and Percentage of a Number — Answer common percentage questions: what is 15% of 200, what percentage one number is of another, or a percentage increase or reduction.
Formula or method
Percent of a value = percentage × value ÷ 100. Relative percentage = part ÷ total × 100. An increase or decrease multiplies the starting value by 1 ± rate ÷ 100.
Worked example
15% of 200 is 30. Increasing 200 by 15% gives 230. 30 as a percentage of 200 is 15%.
How to use the tool
- Choose the percentage calculation type, such as a portion or percentage increase.
- Enter the original values and review the result and formula.
- Compare the answer with your expected unit or total before using it.
Common uses
Tips, discounts, homework, price increases.
When this tool is useful
Work out percentages and increases or decreases without manually rearranging formulas.
What to check before relying on the result
Percentage change from zero is undefined; a negative starting value can change how growth rates should be interpreted.
Assumptions and limitations
The reference value cannot be zero when computing a share of a whole. Tax, stacked discounts and percentage-point changes require their own conventions.
Frequently asked questions
How does this differ from Percentage Change Calculator?
This tool handles several general percentage questions. Percentage Change compares an original value to a new value.
What is 15% of 200?
Multiply 200 by 0.15 to get 30. To find the percentage that 30 is of 200, divide 30 by 200 and multiply by 100.
Continue with a related workflow
Privacy and support
Your inputs are processed locally in your browser. ToolMosaic does not upload or store the values you enter in this tool. Our tools are free, and we appreciate your support.