I tried using the biggerpockets rental calculator this morning and the cashflow was negative, but I may have been too conservative with the numbers.

Do the calculations factor in default rates?

I have a calculator I can send you too.

I mainly want to ask if these assumptions are reasonable and if there's anything I haven't considered:(1) multifamily units in NJ close to New York City, ~$1,000,000, 20% down payment, (2) Using the following assumptions: 4% appreciation rate, 6.5% interest rate and 5.0% refinance after 5 years, $10,000 yearly maintenance fee(3) ~$6,000 monthly rental and assume 3% increase yearly with 5% vacancy rate(4) Based on the above, the calculated IRR if selling at the 10th year is ~19% (considering tax benefits) and ~17% (without tax benefits).

So your capital gain when you sell this property will be calculate against your tax basis and not against your mortgage as many investors expect.

If you're planning on only living there 1-2 years, rent may not change THAT much, so calculate what the rent would likely be right now for your side as well. 4.

Here's the breakdown of rental income and expense analysis:1.Annual Gross Income: $25,800 (Monthly rent of $2,150 x 12)2.Annual Expenses: $25,800 * 0.40 = $10,3203.Annual NOI: $25,800 - $10,320 = $15,4804.Annual Debt Service: $10,680 (Calculated previously using a mortgage calculator with a loan of $131,775, 7.25% interest, and a 30-year term)5.DSCR: $15,480 / $10,680 = 1.45 (approximately)

Tools like the BiggerPockets calculator and books like The House Hacking Strategy can guide you further.

If the bill is $100 a month split between four units, increase it to $120 and charge each tenant $30.How to calculate charges.

Here's a bit more in detail about how rates are calculated for DSCR loans:1.