Profit, cash in, and the 70% screen
Profit is the resale price minus every cost of the project: purchase, rehab, buying costs, selling costs, holding costs, interest, and points. Selling costs are a percent of ARV, which is where an agent fee usually sits. Holding costs are the monthly tax, insurance, and utilities times the months you hold. Interest is separate.
Interest-only financing, the usual short-term setup, charges the loan balance times the annual rate for each month of the hold. Turn that off and the calculator sums only the interest portion of an amortizing schedule. Points are a percent of the loan paid in cash, not rolled into the balance. Loan principal is not a cost. You pay it back at the sale from proceeds, and it reduced the cash you had to bring.
Cash invested is purchase, rehab, buying costs, holding costs, interest, and points, minus the loan. ROI is profit divided by that cash. If the loan covers every dollar of cash cost, ROI is left blank.
The 70% rule on this page is ARV times 70% minus rehab. It answers “what purchase price fits the old screening rule,” not “what you should bid.” If your purchase is above that line, the result says so in dollars. Bring an ARV from the comp estimator when you want the offer and the value to start from the same sales.