Percentage Calculator
Calculate your Percentage result in seconds with the free Percentage Calculator. No registration needed.
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What is a Percentage Calculator?
A percentage calculator is a tool that quickly computes percentage values — such as finding a percentage of a number, calculating percentage change, or determining what percent one number is of another. It saves time and eliminates manual math errors.
How to calculate percentage manually (the formula)
To find a percentage of a number, use the formula: Result = (Percentage / 100) × Number. For percentage change, use % Change = ((New − Original) / Original) × 100. To find what percent X is of Y, use % = (X / Y) × 100.
Example calculation
What is 15% of 200? Using the formula: (15 / 100) × 200 = 0.15 × 200 = 30. So 15% of 200 is 30.
Common mistakes
- Forgetting to divide by 100 — Percent means "per hundred," so you must divide the percentage by 100 before multiplying.
- Confusing percentage change with absolute change — A change from 100 to 150 is a 50% increase, not a 50-point increase in percentage terms.
- Reversing the order in percentage change — Always subtract the old value from the new value, not the other way around.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage (as a decimal). For example, 15% of 200 = 200 × 0.15 = 30.
How do I calculate percentage change?
Subtract the original from the new, divide by the original, and multiply by 100.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100.
What is the formula for percentage?
Percentage = (Part / Whole) × 100.
Can I use this calculator for discounts and tips?
Yes. Enter the original price and the discount or tip percentage to find the final amount.
Is this calculator free to use?
Yes, completely free with no sign-up.