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Percentage Calculator (Increase, Decrease, Convert)

Instantly calculate percent change, convert between fractions, decimals, and percentages, or find the percentage of any number.

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Result:

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    🔍 Overview: What This Percentage Calculator Does

    This free Percentage Calculator helps you calculate:

    • ✅ Percentage of a number (e.g., What is 25% of 80?)
    • 📈 Percentage increase or decrease (e.g., 80 increased by 25%)
    • 🔄 Conversions between percentages, fractions, and decimals

    Whether you're a student solving math homework, a business professional analyzing sales growth, or a shopper figuring out discounts, this calculator gives fast and accurate results.

    📐 Formulas & Calculation Methods

    Here are the main formulas this calculator uses:

    • 1. Find X% of a number:
      \( \text{Result} = \frac{X}{100} \times \text{Base Value} \)
    • 2. Increase a value by X%:
      \( \text{New Value} = \text{Original Value} \times \left(1 + \frac{X}{100}\right) \)
    • 3. Decrease a value by X%:
      \( \text{New Value} = \text{Original Value} \times \left(1 - \frac{X}{100}\right) \)
    • 4. Convert a decimal to a percentage:
      \( \text{Percentage} = \text{Decimal} \times 100 \)
    • 5. Convert a percentage to a decimal:
      \( \text{Decimal} = \frac{\text{Percentage}}{100} \)

    🧮 Example Calculations

    • Find 20% of 150:
      \( 150 \times \frac{20}{100} = 30 \)
      ✅ Answer: 30
    • Increase 200 by 15%:
      \( 200 \times (1 + \frac{15}{100}) = 230 \)
      ✅ Answer: 230
    • Decrease 400 by 25%:
      \( 400 \times (1 - \frac{25}{100}) = 300 \)
      ✅ Answer: 300
    • Convert 0.75 to a percentage:
      \( 0.75 \times 100 = 75\% \)
      ✅ Answer: 75%
    • Convert 30% to a decimal:
      \( \frac{30}{100} = 0.30 \)
      ✅ Answer: 0.30

    📊 Use Cases

    • 🧮 Math homework or test preparation
    • 📉 Finding price discounts during sales
    • 📈 Calculating revenue growth or decline in business
    • 🛒 Determining tax, tip, or service fees on receipts
    • 💰 Understanding interest rates or inflation impact
    • 📓 Converting grades or test scores into percentages

    The tool is designed to be simple enough for kids and flexible enough for financial analysts.

    ❓ Frequently Asked Questions (FAQ)

    How do I calculate a percentage of a number?

    Multiply the base number by the percentage (as a decimal). For example, 20% of 80 is \( 80 \times 0.20 = 16 \).

    What’s the formula for percent increase?

    Use:
    New Value = Original × (1 + X/100)

    Can I use this to calculate tax or tip?

    Yes! For example, to add 8% tax to $100, use:
    \( 100 \times (1 + 0.08) = 108 \)

    How do I convert a decimal like 0.3 to a percent?

    Multiply by 100: 0.3 × 100 = 30%

    What’s the difference between percent and percentage points?

    Percent refers to a relative change, while percentage points refer to an absolute difference between two percentages (e.g., 5% to 7% is a 2 percentage point increase).

    Does this tool round results?

    By default, results are rounded to 2 decimal places for clarity, but you can copy or export full results for precision.

    Can I copy or print my calculation?

    Yes — use the built-in “Copy Results” and “Print/Export” buttons below the output box.