Percentage Calculator

5-in-1 percentage calculator with visual bar chart. Select a mode and enter your values.

Select a mode and enter values to calculate.

How to Use the Percentage Calculator

  1. Choose a mode using the chips above — there are 5 calculation types available.
  2. Enter your numbers in the input fields that appear.
  3. See the result instantly — the answer, explanation, and visual bar update as you type.
  4. Copy the result using the Copy button to use elsewhere.

All Five Calculation Modes Explained

1. X% of Y — Find a Percentage of a Number

This is the most common percentage calculation. The formula is: Result = (X / 100) × Y. For example, 15% of 200 = 30. This mode is useful for calculating tips at a restaurant, discounts on prices, tax amounts, commission earned, and any scenario where you need a fraction of a whole.

2. X is What % of Y — Find the Percentage Rate

Use this when you know two numbers and want to know the percentage relationship. The formula is: Percentage = (X / Y) × 100. For example, "30 is what percent of 150?" = 20%. This is useful for calculating test scores, completion rates, market share, and efficiency ratios.

3. Percentage Change from X to Y

This calculates how much a value has grown or shrunk as a percentage. The formula is: Change = ((Y - X) / |X|) × 100. A positive result means an increase; a negative result means a decrease. For example, going from $40 to $50 is a 25% increase. Use this for price changes, stock returns, population growth, and year-over-year comparisons.

4. Increase or Decrease a Number by a Percentage

This mode applies a percentage to adjust a base value. For increases: Result = X × (1 + Y/100). For decreases: Result = X × (1 - Y/100). For example, increasing 400 by 25% gives 500. This is practical for salary raises, price markups, discount pricing, and inflation adjustments.

5. Fraction to Percentage

Convert any fraction (numerator/denominator) directly to a percentage. The formula is: Percentage = (Numerator / Denominator) × 100. For example, 3/8 = 37.5%. This is useful for converting test scores, ingredient ratios, probability fractions, and statistical proportions into easy-to-communicate percentages.

Practical Uses for Percentage Calculations

Percentage calculations appear constantly in everyday and professional life. Retailers use percentage discounts to advertise sales. Finance professionals calculate percentage returns on investments. Students convert quiz scores to percentages. Nutritionists calculate the percentage of daily values in food. Scientists express concentrations and error rates as percentages. This 5-in-1 calculator handles every common percentage scenario without requiring you to remember formulas. Just pick the mode that matches your question, enter the numbers, and get an instant answer with a clear visual representation. For more advanced statistical analysis, try our Statistics Calculator.

Frequently Asked Questions

To find X% of Y, multiply Y by X and divide by 100. For example, 25% of 200 = (25 × 200) / 100 = 50. Use the "X% of Y" mode in this calculator and enter your values.
Percentage change = ((New Value − Old Value) / Old Value) × 100. A positive result means an increase; a negative result means a decrease. For example, going from 80 to 100 is a 25% increase.
To find what percentage X is of Y, divide X by Y and multiply by 100. For example, 30 is what percent of 120? (30 / 120) × 100 = 25%. Use the "X is what % of Y" mode.
To increase a number by a percentage: New Value = Original × (1 + Percent/100). For example, increasing 500 by 20% = 500 × 1.20 = 600. To decrease: New Value = Original × (1 − Percent/100).
Divide the numerator by the denominator and multiply by 100. For example, 3/4 = (3 ÷ 4) × 100 = 75%. Use the "Fraction to %" mode and enter the numerator and denominator.