Real estate portfolio simulator: complete guide

Open Monetra's real estate portfolio simulator and create a central scenario. This guide then explains its automatic purchase timeline and performance indicators.

The tool answers a focused question: given a repeatable property type, regular savings and consistent assumptions, when does cash make another acquisition possible and what portfolio trajectory follows? It calculates monthly purchases, rent, expenses, debt service, simplified tax, cash, estimated property value, remaining debt and equity.

It is not a registry where existing properties can each receive different assumptions. The current version applies one common property model to every simulated acquisition. That distinction is central to interpreting its output.

The simulation begins with initial cash. It adds monthly savings every month, while the annual bonus is added at the beginning of each new year after the first. It then calculates cash required for the next purchase: down payment, furnishing and, depending on the option, agency and acquisition fees paid in cash.

A purchase occurs when cash can fund that amount and still preserve the minimum cash buffer. The engine may buy several properties in the same month while this test continues to pass. The next property's price grows monthly using the annual property-growth assumption, so rising prices can delay a purchase even while savings accumulate.

Debt-service cap

Entering zero disables this control. Otherwise, Monetra compares aggregate loan payments, including the proposed loan, with the properties' initial gross monthly rent. The internal ratio slows acquisitions in the simulation. It is not a lender's complete household affordability calculation: employment income, other debts, lender treatment of rent and jurisdiction-specific rules are not included.

Paying fees in cash or financing them

When purchase fees are paid in cash, they increase upfront cash but not principal. When financed, they increase the loan and payment. Furnishing remains an initial cash outflow. Compare both versions because the choice changes both acquisition timing and debt cost.

Organize inputs into four groups and record where each estimate came from.

• Acquisition: starting price, property-price growth, fees, furnishing, down payment and fee treatment.
• Financing: rate, term, insurance and optional debt-service cap.
• Operations: starting rent, annual rent growth, vacancy, collection delay, expenses, expense inflation and maintenance reserve.
• Cash and analysis: initial cash, monthly savings, annual bonus, minimum reserve, simplified tax and discount rate.

Start with a cautious case. Price or rent growth should not be used to conceal weak operations. Add a central and downside version with higher vacancy, expenses, purchase prices or rates.

“Simple” tax mode sets tax to zero. “Advanced” mode applies income-tax plus social-charge assumptions to a simplified positive base: effective rent less operating expenses, interest and insurance. It does not reproduce a complete French tax regime, depreciation, deficits, company structures or sale rules. Treat it only as a sensitivity input.

Use the calculator's initial assumptions: a €170,000 property, 3% annual price growth, 6% agency fees, 8% acquisition fees, €5,000 furnishing and a 25-year loan at 3.5%, with 0.2% insurance and no down payment. Fees are paid in cash.

Starting rent is €1,100, with 2% annual growth and 4% vacancy. Operating expenses are €5,000 per year, plus a €1,200 maintenance reserve. The scenario begins with €70,000, adds €800 per month, retains a €10,000 buffer and leaves tax disabled.

Under those assumptions, two properties are bought in the first month, each requiring about €28,800 upfront. A third becomes affordable in month 142, during year 12, at a projected price near €240,595 and an upfront requirement of about €38,683.

At the end of year 25, the model reports approximately €1.065 million of property value, €139,078 of remaining debt and €926,121 of equity. Yet final-year rental cash flow remains negative at about -€5,182. Estimated wealth, equity plus ending cash, reaches roughly €941,828.

This is not a forecast. It relies heavily on constant price growth and automatic acquisitions. The example mainly demonstrates that high projected wealth can coexist with a continuing cash contribution.

Portfolio value applies the chosen appreciation rate to every property. Remaining debt adds outstanding principals. Their difference is equity, which is neither liquid nor guaranteed before an actual sale.

Net rental cash flow subtracts expenses, debt service and simplified tax from rent. Estimated wealth adds equity to ending cash. Gross yield compares final-year rent with final portfolio value; net yield removes expenses and tax but not principal repayment.

The equity multiple, total return on invested cash, IRR and NPV depend on the model's internal cash-flow conventions. They become misleading when initial cash, savings and terminal value do not represent your situation. Use them primarily to compare scenarios built with the same method, not as promised returns.

Save a baseline, duplicate it and alter only one family of assumptions. Compare property count and purchase dates, the lowest cash point, final cash flow, debt and equity. CSV export lets you audit annual rows or continue analysis in a spreadsheet.

For one furnished-rental acquisition and its break-even rent, use the LMNP profitability guide. To validate acquisition financing, see the mortgage simulator guide or multi-loan guide.

The simulator repeats a standardized asset and caps the run at 500 properties. It does not model sales, refinancing, exceptional renovation, insurance claims, tenant default, detailed taxation, disposal costs or local differences between properties. Prices, rents and expenses follow regular growth rates although actual markets move in cycles.

Treat the purchase timeline as a consequence of assumptions, not an acquisition plan. In practice, borrowing capacity, the quality of available properties, management workload and risk tolerance determine whether another purchase is possible or desirable even when simulated cash appears sufficient.