ROI or 1% Rule--which is better?

[Matthew Swearingen]

I have a duplex I might purchase and wanted to get thoughts. Its in c+ area. Each side rents for $750---so $1500 each month. Property has been updated. They are asking $159K. I will put 20% down ($31,800). I'm not sure if there's a mortage calculator out there that is fairly accurate that takes into account PITI and other ancillaries that will give me an accurate monthly net cash....if any one knows of one that they can send me, that would be great. I hate to call a lender everytime and have them work the numbers.

So for the 1% rule of $159k and rents of $1500/mo is just under the 1%. 

I just used a mortgage calculator and came up with the following based on accepted offer of $155K

Financing: 20% down, so financing 131K 30 year at 3.25%

Home insurance $600/year

PITI $540

Tax $76

Insurance $50

Total monthly payment: $765    

ROI= 1500 rents -mortgage 765=$735(12 months)=$8820/31K (down payment)=ROI

ROI =28.45%

Does this look correct. Based on this the cash on cash is good but falls short as far as the 1% rule. I like to be at least 1.5%.

Thank you everyone for your input. I'm fairly new so don't give me insulting comments, which I have never seen on this forum. I want to be encouraged and educated. Not scared off. What got me into this is I'm an ER nurse and got covid from one of my patients and spent 10 days in ICU and got me thinking that I need to have another alternative just in case. But IT IS something I have always wanted to do.