Growth percentage measures an increase in a quantity over time. Business executives, economists, demographers and scientists all analyze different growth percentages when studying their particular industries. Ideally, growth percentages are positive for desirable outcomes such as profit, income and educational attainment, and negative for undesirable outcomes such as obesity, budget deficits and losses. Accurate data collection is the most important (and most difficult part) of calculating growth percentage. The math required to calculate the actual rate is straightforward.

### Step 1

Determine the size in question for the first time period. For example, assume a factory produces 500 widgets in year one.

### Step 2

Determine the size in question for the second time period. For example, assume the factory produces 600 widgets in year two.

### Step 3

Subtract year one production (500) from year two production (600) to yield the increase in production.

### Step 4

Divide the change in production (100) by year one production (500) and multiply the yield (.2) by 100 to find the growth percentage, 20 percent.