Percentage

Percentage Calculator

Quick tools for percentage of, change, and more.

What is X% of Y?

% of
Result
30

Percentage Increase/Decrease

Fromto
Result
+20%Increase
Tip (15%) on 150
22.5
Tip (18%) on 150
27
Tip (20%) on 150
30

How to Calculate Percentages

A percentage represents a number as a fraction of 100. The word itself comes from the Latin per centum, meaning "by the hundred." Percentages are used everywhere — from grading exams and calculating tips, to analyzing financial returns and interpreting statistical data. TheCalcPro's percentage calculator handles the three most common scenarios: finding what percent a number is of another, calculating percentage change between two values, and computing the percentage difference between any two quantities.

The Three Core Percentage Formulas

  • Percentage of a number: P = (Part ÷ Whole) × 100. Variables: Part is the value you're measuring, Whole is the total reference value.
  • Percentage change: ΔP = ((New Value − Old Value) ÷ Old Value) × 100%. A positive result indicates an increase; a negative result indicates a decrease.
  • Percentage difference: D = |V₁ − V₂| ÷ ((V₁ + V₂) / 2) × 100%. This symmetric formula uses the average as the denominator, making it ideal for comparing two independent measurements.

Real-World Example: Calculating a Salary Raise

Suppose your annual salary increased from $52,000 to $56,160. What percentage raise did you receive?

  1. Find the difference: $56,160 − $52,000 = $4,160
  2. Divide by the original: $4,160 ÷ $52,000 = 0.08
  3. Multiply by 100: 0.08 × 100 = 8%

Your salary increased by 8%. This same formula applies to price increases, investment returns, population growth, and any other scenario involving relative change.

Common Applications

Percentages are essential in finance (interest rates, ROI), retail (discounts, markups, sales tax), academics (exam scores, GPA calculation), health (body fat percentage, nutrient daily values), and data science (accuracy metrics, error rates). Whether you're a student checking homework or a business owner calculating margins, this tool delivers instant, accurate results. For more advanced statistical analysis, try our Statistics Engine.

Percentage Calculator FAQ

Use the formula: Percentage = (Part ÷ Whole) × 100. For example, if you scored 42 out of 50 on a test, your percentage is (42 ÷ 50) × 100 = 84%. This formula works for any situation where you need to express a part as a fraction of a total.

Percentage change measures how much a value has increased or decreased relative to its original value: ((New − Old) / Old) × 100%. Percentage difference compares two values symmetrically using their average as the reference: |V1 − V2| / ((V1 + V2) / 2) × 100%. Use percentage change when there is a clear "before" and "after"; use percentage difference when comparing two independent measurements.

To find the discounted price, calculate the discount amount first: Discount = Original Price × (Discount % ÷ 100). Then subtract: Sale Price = Original Price − Discount. For example, a $120 item at 25% off: Discount = 120 × 0.25 = $30, so the sale price is $120 − $30 = $90.

Multiply the pre-tax price by (1 + Tax Rate / 100). For example, if an item costs $45.00 and the sales tax is 8.5%, the total is 45 × 1.085 = $48.83. This single-step formula gives you the tax-inclusive price directly.