Income-Property Math End to End

One storyline covers most investment questions: 20 units at $900/month potential = $216,000 potential gross income; minus 5% vacancy ($10,800) plus $4,800 laundry = $210,000 effective gross; minus $84,000 operating expenses = $126,000 NOI. At an 8% cap rate, value = $126,000 ÷ 0.08 = $1,575,000. Flip any leg: NOI = value × rate; rate = NOI ÷ value. Cash-on-cash return = pre-tax cash flow (NOI − debt service) ÷ cash invested. When a question changes ONE input (raise rents, cut vacancy), rebuild only from that line down — and never let debt service sneak into NOI.