Finance & Money
FinanceConversion
Construction & Other
ConstructionEcologyOther
MathFinanceConversionHealthConstructionPhysicsChemistryBiologyEcologyEveryday LifeFoodSportsStatisticsOther

Percentage Calculator

How To Use

  1. Enter the value you want to calculate the percentage of
  2. Enter the percentage you want to find
  3. Click "Calculate" to see the result

Formula

Result = (Value × Percentage) ÷ 100

How to Use This Calculator

  1. 1

    Pick the calculation type

    Choose whether you need X% of a number, percent change, or what percent one value is of another.

  2. 2

    Enter your values

    Type the base amount, percentage, or old/new values. Use decimals for fractional percents (e.g., 8.25).

  3. 3

    Run the calculation

    Press calculate to see the result instantly. Adjust inputs to compare scenarios side by side.

  4. 4

    Apply the result

    Use the output for pricing, grades, KPIs, or budgets. Round to cents or whole numbers as your context requires.

How It Is Calculated

Percentage math converts between parts, wholes, and rates using division and multiplication by 100.

Percent of Y = (X / 100) × Y | % Change = ((New − Old) / Old) × 100

For “A is what % of B,” compute (A / B) × 100.

Worked examples

Retail discount

A $120 jacket is 30% off: 120 × 0.30 = $36 discount → sale price $84.

Raise at work

Salary rises from $52,000 to $57,200: ((57200 − 52000) / 52000) × 100 = 10% increase.

Exam score

42 correct out of 50 questions: (42 / 50) × 100 = 84%.

When to Use This Calculator

  • Pricing products with discounts, markups, or sales tax
  • Tracking KPI growth (revenue, traffic, conversion rate)
  • Grading, survey results, and completion rates
  • Tip and gratuity calculations at restaurants
  • Comparing before/after measurements in fitness or finance

Common Mistakes to Avoid

  • Adding percentages directly (10% + 15% ≠ 25% of the same base unless applied sequentially)
  • Using the wrong base when calculating percent change (always divide by the original value)
  • Confusing percentage points with percent change (5% → 7% is +2 points, +40% relative change)
  • Forgetting to convert a decimal to percent (0.08 = 8%, not 0.08%)

Frequently Asked Questions

How do I find what percent A is of B?

Divide A by B, then multiply by 100. Example: 45 is what percent of 200? 45 / 200 = 0.225, which is 22.5%.

How do I calculate a percentage increase?

Use ((new value - old value) / old value) x 100. Example: price rises from $80 to $92: (12 / 80) x 100 = 15% increase.

How do I find X% of a number?

Multiply the number by (X / 100). Example: 15% of 200 = 200 x 0.15 = 30.

Can I use this for discounts and tax?

Yes. A 20% discount multiplies the price by 0.80. Adding 8% tax multiplies by 1.08. Combine steps in the order your receipt requires.