How to Calculate the Loan Constant (Cost of Capital)

The cost of capital for a property is called the LoanConstant = .07916 x 100 = 7.916% (rounded)
Constant (Constant) or Mortgage Constant. All loansSince the borrower knows the Debt Service
have a certain interest rate and, unless there is anCoverage Ratio must be 125% more than annual debt
interest-only portion to the loan, all loans will require apayments he can calculate the annual payments as
principal and interest payment. The principal isthe following:
calculated based upon the amortization of the loan.$560,000 = $448,000
Thus, if the loan has a 30-year amortization, which is1.25
equal to 360 months, the principal must be paid in 360With $448,000 of the property's net operating income
installments so the loan is paid in full on the last loanavailable to service the debt payments, his maximum
payment.possible mortgage based on debt service would be:
The quoted interest rate of a loan is strictly the$448,000 = $5,659,424
amount of interest that loan accrues. The loan.07916
constant, on the other hand, is expressed as anAs illustrated, the loan constant is a tool that can help a
interest rate that incorporates both the interest andborrower easily understand the potential debt service
principal repayment of a loan. The formula is:associated with a property based upon a certain net
Loan Constant = [Interest Rate / 12] / (1 - (1 / (1 +operating income. Any borrower should make sure
[interest rate / 12]) ^ n))n = the number of months inthey check the loan constant with their lender to
the loan termensure that it matches his assumptions. For example,
Example 1: Suppose an investor received a loan forFHA multifamily mortgages have a mortgage
$4,000,000 at a 5.50% interest rate with a 30-yearinsurance premium that is also factored into the loan
amortization. We can calculate the required annual loanconstant which raises a property's cost of capital. A
payments once the loan constant is known.few other items to remember are:
Constant = [.055 / 12] / (1 - (1 / (1 + (.055 / 12]) ^ 360))Shortcoming #1: The constant only works for fixed
Constant = .06813 x 100 = 6.813% (rounded)rate loans. For adjustable rate mortgages that have
Annual payments = $4,000,000 * .06813 = $272,520changing monthly interest rates lenders will typically
While the property has an interest rate of 5.50% theunderwrite the maximum possible interest rate for that
investor's actual cost of capital for the loan is 6.813%loan. Find out from your lender what is appropriate
once the principal payment has been factored. If thewhen modeling debt assumptions.
above loan scenario has a 1.25x debt serviceShortcoming #2: The constant changes based upon
coverage ratio (DSCR) requirement then an investorthe amortization of the mortgage. While not
knows that the property must have at least thenecessarily a shortcoming, it is important to understand
following NOI to support the loan:the terms of any loan quote you receive from a lender
$272,520 x 1.25 = $340,650or if your loan assumptions are accurate for a
Consider that the reverse also holds true. A borrowerparticular property or market. The shorter the
can factor his potential debt service loan with the loanamortization period of a loan, the higher the property's
constant as long as he knows the NOI.cost of capital.
Example 2: A borrower wants to refinance his loan.Shortcoming #3: The constant does not factor
His NOI is $560,000 and he has heard that his localinterest-only periods. In the current lending
bank will give him an interest rate of 6.25% for 25environments, most lenders use an amortizing constant.
years with a minimum DSCR of 1.25. What is theWhen modeling cash flow it is important to note an
maximum loan he can borrower subject to aninterest only periods but although it will increase the
appraisal?cash-on-cash returns, it will not change the loan
Constant = [.0625 / 12] / (1 - (1 / (1 + (.0625 / 12]) ^amount.
300))