Most landlords can tell you their rent amount. Very few can tell you their actual monthly profit. The gap between those two numbers is where financial decisions go wrong and where the illusion of a successful investment quietly erodes into a break-even operation. Calculating real monthly profit requires more than subtracting a mortgage payment from a rent check. It requires a structured, honest accounting of every cost the property generates, including the ones that do not show up on a monthly bank statement. Here is how to build that calculation correctly.

Step One: Start With Gross Rent, Not Net Rent

The starting point is gross scheduled rent — the full amount the property would generate if occupied every month of the year. Divide the annual gross rent by twelve to establish your monthly baseline, then subtract a vacancy allowance. In most Texas markets, a realistic vacancy rate for a well-managed single-family rental runs between 5% and 8% of gross annual rent. On a property renting for $2,000 a month, a 6% vacancy allowance reduces effective monthly revenue to approximately $1,880. This adjustment is not pessimism; it is accuracy. Every property will experience vacancy at some point, and a profit calculation that assumes 100% occupancy every month is not a real number.

Step Two: Subtract Fixed Operating Expenses

Fixed operating expenses are the recurring, predictable costs required to keep the property legally compliant and structurally insured. These include property taxes, homeowner’s insurance, and any HOA fees. These numbers should be annualized and divided by twelve to produce a true monthly figure.

Property taxes in Texas are assessed annually, but their monthly impact on your cash flow is constant. A property with a $6,000 annual tax bill carries a $500 monthly fixed expense, regardless of when the bill arrives. The same logic applies to insurance premiums. If your landlord policy costs $1,800 per year, that is $150 per month that belongs in the expense column every single month, not just in the month the premium is due.

Step Three: Subtract Variable Operating Expenses

Variable operating expenses are the day-to-day maintenance and management costs that fluctuate month to month: routine repairs, lawn care, pest control, and property management fees. Because these costs are irregular, calculate a trailing twelve-month average and use that figure as your monthly estimate. If you spent $3,600 on variable expenses over the past year, your monthly estimate is $300. This figure will not be exact every month, but it will be accurate over time. If you use a property management company, their fee, typically 8% to 10% of collected rent, belongs here as a fixed line item.

Step Four: Subtract the Cap Ex Contribution

This is the step most landlords skip, and it is the reason their profit calculations are wrong. Capital expenditure reserves are not optional savings. They are a real cost of ownership that must be accounted for monthly, even when no major repair is currently needed.

Calculate the replacement cost and remaining useful life for each major system: the roof, HVAC, water heater, flooring, and appliances. Divide the replacement cost by the remaining months of useful life to determine the monthly contribution required to be fully funded at replacement time. On a typical Texas single-family rental with systems of average age, this number often falls between $150 and $350 per month. It belongs in the expense column before you calculate profit.

Step Five: Subtract Debt Service

After all operating expenses and Cap Ex contributions have been subtracted from effective gross revenue, you arrive at Net Operating Income. From NOI, subtract the monthly mortgage payment. The result is your true monthly cash flow. Note that only the interest portion of the payment is a true expense; the principal paydown builds equity. For the purpose of calculating monthly profit, however, the full debt service payment is subtracted from NOI to produce the cash flow figure you can actually spend or reinvest.

What the Number Tells You

A complete monthly profit calculation for a $2,000 rent property might look like this: effective gross revenue of $1,880 after vacancy, minus $650 in fixed expenses, minus $300 in variable expenses, minus $250 in Cap Ex contributions, minus $1,200 in debt service, produces a true monthly profit of negative $520. That property is not profitable. The gross rent figure obscured that reality entirely.

Running this calculation for every property in your portfolio is the most clarifying exercise a small landlord can perform. It reveals which properties are genuinely earning their keep, which ones are breaking even, and which ones are quietly consuming capital. That information is the foundation of every intelligent decision about whether to hold, improve, or divest an asset.