how do i calculate percentage of growth

If you’ve ever asked, “How do I calculate percentage of growth?”, you’re asking one of the most useful math questions in business, personal finance, sales, and analytics. The good news: it’s simple once you know the formula.

Whether you are tracking revenue growth, salary growth, website traffic growth, investment performance, or student performance over time, percentage growth helps you compare change fairly across different starting points.

The Basic Percentage Growth Formula

Use this formula:

Percentage Growth = ((New Value - Old Value) / Old Value) × 100

In plain English:

• Subtract the old value from the new value to get the change.
• Divide that change by the old value.
• Multiply by 100 to convert to a percentage.

Step-by-Step: How to Calculate It Manually

1) Find the old value and new value

Example: old value = 200, new value = 260.

2) Calculate the difference

260 - 200 = 60

3) Divide by the old value

60 / 200 = 0.30

4) Convert to percentage

0.30 × 100 = 30%

Final answer: 30% growth.

Worked Examples

Example 1: Revenue Growth

Your monthly revenue increased from $8,000 to $10,000.

• Change = 10,000 - 8,000 = 2,000
• Growth rate = 2,000 / 8,000 = 0.25
• Percentage growth = 25%

Example 2: Website Traffic Growth

Traffic rose from 50,000 visits to 65,000 visits.

• Change = 15,000
• Growth = 15,000 / 50,000 = 0.30
• Percentage growth = 30%

Example 3: Negative Growth (Decrease)

Customers dropped from 500 to 425.

• Change = 425 - 500 = -75
• Growth = -75 / 500 = -0.15
• Percentage growth = -15%

A negative percentage means decline, not increase.

How to Calculate Growth Across Multiple Years (CAGR)

When growth happens over several periods, you might want an average per year (or per month). For that, use CAGR (Compound Annual Growth Rate).

CAGR = ((Ending Value / Starting Value)^(1 / Number of Periods) - 1) × 100

Example: An investment grows from 10,000 to 15,000 over 4 years.

• 15,000 / 10,000 = 1.5
• 1.5^(1/4) - 1 ≈ 0.1067
• CAGR ≈ 10.67% per year

This gives a smoother “average annual growth rate” than simple total growth.

Common Mistakes to Avoid

• Using the new value in the denominator: always divide by the old (starting) value for standard growth calculations.
• Forgetting to multiply by 100: 0.18 means 18%, not 0.18%.
• Mixing units: don’t compare dollars to thousands of dollars without conversion.
• Ignoring negative signs: a minus sign tells you it’s a decrease.

What If the Starting Value Is Zero?

If the old value is 0, standard percentage growth is undefined because division by zero is impossible. In this case, describe the change in absolute terms (for example, “grew from 0 to 120 users”) or use a different metric.

Quick Reference

• Growth %: ((new - old) / old) × 100
• Decrease %: same formula (result becomes negative)
• Average multi-period growth: use CAGR formula

Bottom Line

To calculate percentage of growth, subtract old from new, divide by old, then multiply by 100. That single formula can power better decisions in budgeting, forecasting, investing, and performance tracking. If you want quick results, use the calculator above and test your numbers instantly.