Financial Glossary
Mortgage Constant
The mortgage constant, also called the loan constant, is the annual debt service on a fully amortizing mortgage expressed as a percentage of the original loan amount. It combines both principal and interest into a single ratio, allowing real estate investors and lenders to quickly compare the cost of debt across different loan structures, interest rates, and amortization periods. A higher mortgage constant means higher annual payments relative to loan size; a lower constant means lighter annual debt service and typically more favorable leverage economics for the borrower.
Problem & Application
Real estate operators evaluating a purchase or refinance often compare properties using cap rates, but cap rate alone does not reveal whether the debt service is manageable. Comparing the property's cap rate to the mortgage constant tells the investor whether the deal is positively or negatively leveraged: if the cap rate exceeds the constant, debt amplifies returns; if the constant exceeds the cap rate, every dollar of borrowed money actually dilutes cash-on-cash yield. For STR and campground operators working with commercial lenders, understanding this relationship is foundational to structuring acquisitions that generate positive cash flow rather than just equity buildup.
In Short
The mortgage constant is a simple but powerful ratio for stress-testing acquisition economics. Operators who internalize it can quickly screen financing scenarios and avoid deals where leverage works against them.