Percentage Calculator
Calculate any percentage instantly — percent of a number, what percent one value is of another, or the percentage change between two values.
Fast, Accurate Percentage Calculations
Three calculation modes in one tool — no switching between different calculators.
Percent of a Number
Find exactly how much a percentage represents. Enter the percent and the base value — get the answer instantly.
What Percent
Find what percentage one number is of another. Perfect for test scores, ratios, and proportions.
Percentage Change
Calculate increase or decrease as a percentage. Know exactly how much something grew or shrank.
Three Modes in One
Switch between percent-of, what-percent, and percent-change without leaving the page.
Instant Results
No loading, no server calls. All math runs directly in your browser as you type.
100% Free & Private
No sign-up, no tracking. Your numbers never leave your device.
Who Uses This Calculator
From students to finance professionals — one tool for every percentage problem.
Students & Teachers
Calculate test scores, grade percentages, and class averages in seconds.
- Convert raw scores to percentages
- Calculate grade cutoffs
- Understand proportional relationships
Shopping & Finance
Work out discounts, tax amounts, price increases, and savings at a glance.
- Calculate sale savings
- Find percentage of salary for budgeting
- Track portfolio percentage changes
Business & Analytics
Measure growth rates, market share, conversion rates, and performance metrics.
- Revenue growth calculation
- Conversion rate analysis
- Year-over-year comparisons
How to Calculate Percentages
Select the calculation mode — percent of a number, what percent, or percentage change.
Enter the two values in the input fields provided for your chosen mode.
Click Calculate and get your result instantly — no waiting, no page reload.
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Frequently Asked Questions
Common questions about percentage calculations.
How do I calculate what percent X is of Y?
Divide X by Y and multiply by 100. For example, 40 is what percent of 200? → (40 ÷ 200) × 100 = 20%. Use the 'X is what % of Y' mode and the calculator handles this automatically.
How do I calculate percentage change?
Percentage change = ((New − Old) / |Old|) × 100. A positive result means increase; a negative result means decrease. The 'Percentage change from X to Y' mode calculates this for you.
What is X% of Y?
Multiply Y by X and divide by 100. For example, 15% of 80 = (15 × 80) / 100 = 12. Use the 'X% of Y' mode for this calculation.
Are results rounded?
Results are shown with up to 4 decimal places, with trailing zeros removed. For whole-number answers, only the integer is shown.