The total percentage return measures how well your investment has done during a specified time period. Using percentages allows you to measure the gain relative to the amount invested, which is more useful than just the dollar amount of gain or loss. The downside to using the total return is that multiple year periods can differ drastically in length. For example, a 15 percent return over two years is likely a solid return, but that same 15 percent return isn't nearly as attractive over 10 years.
Subtract your initial investment value from the ending investment value to find the gain or loss. For example, if you want to calculate the total percentage investment return over a five-year period, use the value at the start of the first year and the value at the end of the fifth year. If it started at $8,000 and grew to $10,200, your investment gain is $2,200.
Divide the gain or loss by the initial investment value to find the overall rate of return. In this example, divide $2,200 by $8,000 to get 0.275.
Multiply the growth rate by 100 to find the total percentage investment return over the multi-year period. Finishing the example, multiply 0.275 by 100 to find the investment grew by 27.5 percent over the five-year period.
- Thinkstock Images/Comstock/Getty Images