Dollar Weighted Rate of Interest

If you want to calculate the dollar weighted rate of interest return, use this calculator.  This solves for interest rate return and net investment income.  The formula is interest rate return (i) equals:

i = 2 * (Investment Income - Investment Expense)/(Asset at Beginning of Period + Asset at End of Period - Net Investment Income) where:

Asset at End of Period = Asset at Beginning of Period + All Income - All Expenses

Net Investment Income = Investment Income - Investment Expenses

Example:  You are given an asset value of 10 million at 1/1/2008.  During the year, income is 1,530,000 of which 530,000 is investment income.  Also, 620,000 of expenses occur in which 20,000 are investment expenses.  Find the interest rate of return at 12/31/2008. 

First, you press solve for Interest Rate.  Enter 10,000,000 for asset value, 1,000,000 for income, 530,000 for investment income, 20,000 for investment expenses, 1,000,000 for other income and 600,000 for other expenses and press calculate.  Interest rate of return = 5%.