How to Calculate Percentage of Monthly Growth

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If you've ever wanted to track how website visitors, social media likes, stock values or company sales change over time, you've made a case for calculating the percentage of monthly growth. This figure tells you more than how much each of those figures has changed; it also tells you how big or small the change was when compared to the starting value. For example, a rise or fall of 1,000 Instagram followers isn't even a blip on the radar for social media giants like Taylor Swift and Selena Gomez, but the same number is a big deal – and a big percentage change – for someone who's just starting out.

TL;DR (Too Long; Didn't Read)

To calculate the percentage of monthly growth, subtract the previous month's measurement from the current month's measurement. Then, divide the result by the previous month's measurement and multiply by 100 to convert the answer into a percentage.

  1. Find the Amount of Change

  2. To find the amount by which whatever you're measuring has grown, subtract last month's measurement from the current month's measurement. For example, if this month you have 2500 Instagram followers and last month you had 2,000, you calculate 2,500 − 2,000 = 500. Your Instagram following has changed by 500 followers.


    • Heads up! The amount of your growth can be positive or negative. If you had lost 500 Instagram followers over the last month instead of gaining them, your change would be -500.

  3. Divide by Last Month's Measurement

  4. Divide the amount of change by the previous month's measurement. To continue the example, you'd have 500 ÷ 2,000 = 0.25.

  5. Convert to Percentage

  6. Multiply the result from the last step by 100 to turn it into a percentage. So, 0.25 × 100 = 25 percent. Your Instagram following grew by 25 percent in the last month.

Another Example

You can use the percentage of monthly growth to calculate how much a value has shifted over any two months – they don't have to be recent. For example, let's say you worked in a toy store last year, and the owner wanted to know how much sales jumped from November to December as the Christmas rush came into full swing. If the store sold $10,000 worth of toys last November and $24,000 worth of toys last December, what was the percentage of monthly change?

  • $24,000 − $10,000 = $14,000 (finding the amount of change)
  • $14,000 ÷ $10,000 = 1.4 (dividing by last month's measurement)
  • 1.4 × 100 = 140 percent (converting to a percentage)

So, last year the sales jumped 140 percent from November to December.


About the Author

Lisa studied mathematics at the University of Alaska, Anchorage, and spent several years tutoring high school and university students through scary -- but fun! -- math subjects like algebra and calculus.