Pick the question type
Choose what you need: a percentage of a number, a part as a percentage of a whole, or the change from one value to another.
Calculators
Percentage Calculator
Free online percentage calculator
Enter the values
Local processingResult
The result will appear here after you run the tool.
Press Ctrl or Command and Enter to run the tool.
About this tool
About this tool
Percentage Calculator covers percent-of, part-of-whole, and percent-change questions using simple arithmetic in your browser. Choose the calculation type, enter the two required values, and read the result with the underlying formula and a brief explanation. All math is local and instant.
Solve everyday percentage questions without mental math. The tool handles the three most common cases: what a percentage of a number is, what share one number represents of another, and how much a value changed in percentage terms. Pick the type, enter two numbers, and the answer appears with the formula that produced it.
Built for daily work
- Work out 15 percent of a bill for a tip estimate.
- Find what percentage of a monthly budget a category uses.
- Measure sales growth from one quarter to the next.
- Check the percent change in a stock or price index.
How to use this tool
How to use this tool
Enter two numbers
The tool shows exactly the two fields your selected type needs, so there is no guessing about which value goes where.
Read the answer and formula
The result appears with the formula shown, which makes the calculation easy to verify or reuse.
Key features
Key features
Three common modes
Percent of a number, part of a whole, and percent change cover most daily percentage questions in one tool.
Formula transparency
Every result includes the expression that produced it, helping you understand and verify the math.
Adaptive fields
Only the fields needed for the selected mode are shown, keeping the form clean and unambiguous.
Instant local math
Results update with the Calculate button and are computed entirely on your device.
Practical use cases
Practical use cases
- Work out 15 percent of a bill for a tip estimate.
- Find what percentage of a monthly budget a category uses.
- Measure sales growth from one quarter to the next.
- Check the percent change in a stock or price index.
- Convert a fraction share into a percentage for a report.
Private by default
For local tools, input is processed in your browser and is not sent to application analytics.
Data processing noticeTechnical details
Technical details
ProcessingLocal browser processing
ModesPercent of, part of whole, percent change
InputFree numeric entry
OutputResult with formula and explanation
Limitations and important notes
Limitations and important notes
- The tool answers arithmetic questions, not compound or reverse percentage problems.
- Percent change from zero is undefined and rejected.
- Rounding is display-only.
Frequently asked questions
Frequently asked questions
Multiply X by Y and divide by 100. For example 15 percent of 200 is 15 x 200 / 100 = 30.
It is the difference between two values divided by the starting value, expressed as a percentage. A rise from 100 to 120 is a 20 percent increase.
No. Division by zero is undefined, so the tool asks for a non-zero starting value.
Display is rounded for readability; the internal calculation keeps full precision.
Related guides and solutions
Related guides and solutions
Calculate a percentage increase in seconds
Salary changes, price rises, revenue growth, and cost increases are all percentage increase questions. Enter the original and new values, and the calculator returns the percentage increase with the difference and the formula.
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Learn moreHow to calculate a tip and split a bill fairly
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