For debt service, I would use at least conservative 75 LTV(25 down) 6% IR a 25 amortization for multifamily on a conventional term to get an understanding of cash flow after debt and calculate cash on cash. 30-year amortization is likely but it depends on the location and it's a case by case.

I actually faced a similar dilemma with my personal property what I recommend is make the calculation over the next few years how how much each options is likely to generate and compare them side by side, it really helps to make an educated decision.

For debt service, I would use at least conservative 75 LTV(25 down) 6% IR a 25 amortization for multifamily on a conventional term to get an understanding of cash flow after debt and calculate cash on cash. 30-year amortization is likely but it depends on the location and it's a case by case.

Guys when using the bp calculator.

The floor area shall be calculated on the basis of the total area of all habitable rooms.

So I ran the calculations for BRRRR and we'll cash flow about $200 a month (after refi). 

@Dan HeuscheleThanks for the detailed example, so to get your 30K profit did you calculate 70% rule ARV x70% minus the rehab cost?

I tried to use the calculator but still couldn’t figure out what’s bestRent: possibly $1,250/month (3bed/2.5bath)Sale: comps for exact home or slightly smaller recently sold for around $160kWith rent I know there are addition expenses: vacancy- tenant repairsHOA: $25/monthMortgage/Tax/Insurance: $830/month Water: not sure I think I average around $30/month possibly.

Is there any way I could calculate the mortgage after the rehab, does having equity in the property bring down the mortgage?

Is there any way I could calculate the mortgage after the rehab, does having equity in the property bring down the mortgage?