How do I know if the rent will actually cover my costs?

Rent covers your costs when it exceeds the full carrying cost of the property: the mortgage payment, property taxes, insurance, routine maintenance, and a reserve for vacancy and repairs, not just the mortgage alone. Many first-time investors compare rent only against the mortgage payment and miss the rest, which makes a deal look better than it actually is. Joel Boss can help pull comparable rents and build out the full cost side for a specific property you're evaluating.