how to find percentage of something

To find the percentage of something, you always compare a part to a whole using a simple formula:

Percentage=partwhole×100\text{Percentage}=\frac{\text{part}}{\text{whole}}\times 100Percentage=wholepart​×100

Quick Scoop: Core Idea

If you know:

• the part (the amount you care about), and
• the whole (the total amount),

then:

Percentage = (part ÷ whole) × 100

Example:
You scored 42 points out of 50 on a test.

4250×100=84%\frac{42}{50}\times 100=84%5042​×100=84%

So, you got 84%.

Mini Guide: Three Typical Cases

1. Find “What percent is this?”

Use when you know both numbers and want the percentage. Formula:

Percent=partwhole×100\text{Percent}=\frac{\text{part}}{\text{whole}}\times 100Percent=wholepart​×100

Example:

• 20 out of 80 are red: 2080×100=25%\frac{20}{80}\times 100=25%8020​×100=25%
• So 25% of the items are red.

2. Find “What is X% of a number?”

Use when you know the percentage and the whole. Steps:

1. Convert the percent to a decimal.
   • 30% → 0.30
2. Multiply by the whole.

Example:

• 30% of 200: 0.30×200=600.30\times 200=600.30×200=60
• So 30% of 200 is 60.

3. Find “The whole, if I know a part and the percent”

Use when you know:

• the percentage, and
• the part (the result),

and you want the original total. Formula:

Whole=partpercent as decimal\text{Whole}=\frac{\text{part}}{\text{percent as decimal}}Whole=percent as decimalpart​

Example:

• 45 is 15% of what number?
  • Percent as decimal: 15% → 0.15
  • Whole = 45 ÷ 0.15 = 300
• So 45 is 15% of 300.

Quick HTML Table (for reference)

html

<table>
  <thead>
    <tr>
      <th>What you want</th>
      <th>What you know</th>
      <th>Use this formula</th>
      <th>Example</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Percent</td>
      <td>Part and whole</td>
      <td>(part ÷ whole) × 100</td>
      <td>20 out of 80 → (20 ÷ 80) × 100 = 25%</td>
    </tr>
    <tr>
      <td>Part</td>
      <td>Percent and whole</td>
      <td>part = (percent ÷ 100) × whole</td>
      <td>30% of 200 → (30 ÷ 100) × 200 = 60</td>
    </tr>
    <tr>
      <td>Whole</td>
      <td>Part and percent</td>
      <td>whole = part ÷ (percent ÷ 100)</td>
      <td>45 is 15% of what? → 45 ÷ 0.15 = 300</td>
    </tr>
  </tbody>
</table>

Tiny Story Example

Imagine a store has a sale sign: “25% off all jackets.”

• Original price = 80
• Discount = 25% of 80 = 0.25×80=200.25×80=200.25×80=20
• New price = 80 − 20 = 60

Same idea works for tips, grades, discounts, interest, and more.

SEO Bits You Asked For

• Focus keyword: how to find percentage of something
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TL;DR:

• Percentage = (part ÷ whole) × 100
• X% of a number = (X ÷ 100) × whole
• Whole = part ÷ (percent ÷ 100)