Determine your investment's current value. This is done in different ways, depending on the type of investment. For an investment such as stocks, for example, multiply the current individual share price by the number of shares you have.
Subtract the initial investment amount from the current value you calculated. This shows your capital gains or losses.
Add dividends, or extra money received, to the capital gains or losses. This gives the total gain or loss amount.
Divide the total gain or loss by your initial investment amount, and then multiply that number by 100. You have calculated the percent loss.