Improvement percentage is the ratio of positive change from one number to a higher number as expressed by a percentage. Workers in fields such as accounting and finance use improvement percentage to measure increases in income, profit or expenses, while athletes might use improvement percentage to measure increased speed, endurance or weightlifting ability. With or without a calculator, understanding how to calculate this measure of growth helps with evaluating performance across any sector or project.
Determine the two base numbers you will compare. For instance, if comparing income from one month to the next, have those numbers ready to use in the ratio. The first number is the base number against which you will judge the improvement of the second number.
Subtract the first number from the second number. Using income as an example, if comparing a $400 income in one month to a $500 income in the second, subtract $400 from $500 to get $100.
Divide the result from Step 2 by the first number. Using the same example for income, divide 100 by 400, getting a result of 0.25.
Convert 0.25 to a percentage by multiplying by 100. The answer in the example is 25 percent; the improvement percentage in income was 25 percent from one month to the next.
It's easy to confuse the denominator and numerator when calculating improvement percentage; always double-check work.