Growing portfolio will I hit DTI and DSCR wall?

[Christian Allen]

Recently been thinking about how the bank views rental income and your personal debt to income (DTI) ratio. From what I've read and experienced with my two properties, banks will typically take 75% of your rental income and Fannie Mae guidelines require your DTI to be no greater than 0.43. Based on these numbers the debt service coverage ratio you would need to continue to buy properties without getting closer to the DTI ratio limit is 3.1. The proof for this is as follows. DTI=(total payments)/(total income). In the case of a rental property Max DTI=0.43>=(total payment)/(gross rent*0.75) Solving for gross rent you would get: gross rent= 3.1*total mortgage payment. An example with numbers: Mortgage payment-$1000 0.43=(1000)/(gross rent*0.75) Gross rent=$3100.77 (plug in and verify if you don't believe me) Does this mean for a property to not continue to increase my DTI I need to have the rent be 3.1 times the mortgage payment or am I missing something? Are there lenders who calculate DTI differently?