What is a cumulative return?
The cumulative return on an investment is pretty much what it sounds like. It's the total return of an investment over the period of time you've held it. This is just the basic return, not including the effects of compounding or any rolled-in dividends.
You need very little information and just a calculator to do this math -- it's a great, easy calculation for beginning investors to use to review their investments. Not only is it fun to see how much your investment has grown, but it can also tell you if that investment is really going to help you meet your investment goals.
How to calculate cumulative return
The formula for cumulative return is remarkably simple.
Cumulative Return = (Current investment value - Initial cost of investment) / Initial cost of investment
So, if you bought shares of ABC Corp. for $40 each and they're now worth $100 each, here's how the math goes:
CR = (($100 - $40) / $40) * 100
CR = ($60 / $40) * 100
CR = 150%
Pretty sweet return -- or is it? This is one downside to cumulative return as a sole measure of success or failure with a stock. Since it's for the entire life of your investment, a dip in the market can make your investment look awful, or a great week can make it look really good. It's important to consider other types of assessments when evaluating your returns before making big decisions like buying or selling.