Calculating cash flow on a duplex

[Marc Ferguson]

Hi, I'm very new to real estate investing. I used BiggerPockets' rental calculator to see what a single family home would look like. Very cool tool. I'm now trying to do it manually so that I have a better understanding of how to run-the-numbers. Can you help verify if I did this correctly and if I'm missing anything. Thank you for any guidance you can provide.

DUPLEX

Purchase price: $210,000
Closing cost (2%): $4,200
Down payment (20%): $42,000
Annual property value growth (appreciation): 2%

Loan
Loan amount: 168,000
Interest rate: 3.042%
Points charged: ?
Loan term: 30 years

Rental income
Gross monthly income: $1,100 x 2

Monthly expenses
Property taxes: $189 ($2,268)
Insurance: $90
Repairs & maintenance: $55
Vacancy: $33
Capital expenditures: $55
Management fees: $55
Electric: $123 x2
Water & sewer: $40 x2
HOA fees: $0
Garbage: ?

Total income: $2,200
Total expenses: $803
Mortgage: $859
CASH FLOW: $538