How is annualized rate of return calcuated for an investment where cash is added at irregular intervals?

For instance, suppose you have a mutual fund holding and you continue to buy into it and sell out of it at random times.





Assume intial data is a spreadsheet with transaction dates, share prices, transaction dollar amount and value of the fund at the time of each transaction. I want to be able to calculate the annualized rate of return for the fund overall, or for any given time period.





This is just a single instance of a particular problem. Another would be, how to get average annual ROI on say, just your foreign stocks, when money keeps flowing in and out of the foreign stock pool.





I hope someone can answer this! The longer I try to derive how to compute this, the more brain-dead I feel. I give up; how is it done?|||When the cash inflow and outflow are irregular, the ROI is calculated by using the Internal Rate of Return methodolgy. Use Wikipedia to understand the IRR calculation formula and input your numbers into the formula to calculate your rate of return.|||Use Internal Rate of Return. Excel has it. Or you can use a financial calculator. Or maybe there is an online calculator.