Free Online Percentage Calculator

Solve four common percentage problems with live instant calculations, formulas, and explanations.

What is X% of Y?

What is % of ?
Result
30
Formula: (15 ÷ 100) × 200 = 30

X is what % of Y?

is what % of ?
Result
25%
Formula: (45 ÷ 180) × 100 = 25%

Percentage Increase

From to
Percentage Change
+50.00%
Formula: ((75 - 50) ÷ 50) × 100

Percentage Decrease

From to
Percentage Reduction
-20.00%
Formula: ((100 - 80) ÷ 100) × 100
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About Free Online Percentage Calculator

Solve common percentage math problems quickly with clear formulas and step-by-step solutions. Calculate what X% of Y is, determine what percentage X is of Y, and compute percentage increases or decreases for finance, retail, and academia.

How to Use Free Online Percentage Calculator Online

1
Select Calculation Mode
Choose between: (1) What is P% of X, (2) X is what percentage of Y, or (3) Percentage change from X to Y.
2
Enter Your Values
Type numbers into the designated input fields. Results calculate instantly on every keystroke.
3
Inspect Calculation Formula
Review the mathematical formula and step-by-step arithmetic steps displayed alongside the answer.
4
Copy Result
Click Copy Result to paste the computed percentage into your spreadsheet, invoice, or homework.

Key Features & Privacy Benefits

  • Triple Computation Engine: Covers the three most common daily percentage problems in one unified, uncluttered interface.
  • Step-by-Step Educational Formulas: Shows the exact algebraic equation so students and professionals can verify the mathematical working.
  • High Precision Floating Math: Eliminates rounding drift by calculating floating point decimals accurately to multiple decimal places.
  • Instant Live Calculation: No submit buttons or page refreshes. Values update dynamically as you type.

Frequently Asked Questions

Percentage change is calculated by subtracting the initial value from the final value, dividing by the absolute initial value, and multiplying by 100: ((Final - Initial) / Initial) * 100.
Divide the score by the total possible points and multiply by 100. For example, 45 out of 60 is (45 / 60) * 100 = 75%.
Yes. When calculating percentage change, a negative result indicates a percentage decrease (loss), while a positive result indicates growth.

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