The REI Vault Pro Rental Property Calculator: Run a Complete Investment Analysis on Any Buy-and-Hold Deal

Buy-and-hold real estate investing is a long-term game, and the decisions you make at acquisition determine your returns for years — sometimes decades. Getting those decisions right requires more than a single calculation. It requires a complete, structured analysis that covers cash flow, return metrics, income performance, and quick-screen rules — all applied consistently to every property you evaluate.

The REI Vault Pro Rental Property Calculator is that complete analysis in one place.

What Separates a Complete Rental Analysis from a Partial One

Most investors run partial analyses. They calculate the cash flow. Or they check the cap rate. Or they run the 1% rule. Each of these metrics tells you something useful — but none of them tells you everything. A property can pass the 1% rule and still cash flow poorly after expenses. A property can have an attractive cap rate but fail to produce acceptable cash-on-cash return at your financing terms. You need all of the metrics together to see the full picture.

The Rental Property Calculator runs all of them — the complete cash flow model, cap rate, cash-on-cash return, NOI, and the quick-screen rules — from a single set of inputs.

The Full Input Set

Financing Inputs

Purchase Price — the acquisition cost. Down Payment % — your equity contribution, which determines leverage and monthly debt service. Interest Rate — the rate on your investment property loan. Together these three inputs generate your loan amount and monthly mortgage payment, which is typically the largest single expense in the model.

Income and Vacancy

Monthly Gross Rent — the market rent the property will command in its post-renovation condition. Pull active comparable rentals within half a mile to validate this number. Vacancy Rate % — budget 5–8% for stable rental markets, 10% for transitional or softer markets. This is the percentage of annual gross rent lost to vacancy and turnover.

Operating Expenses

Property Taxes (monthly) — the actual current tax bill divided by 12. Available on the public record for every property. Insurance (monthly) — landlord insurance, typically $100–$200/month for single-family. Maintenance (monthly) — 1% of property value annually divided by 12, as a baseline. Property Management % — budget 8–10% of gross rent even if you currently self-manage. CapEx Reserves (monthly) — 8–10% of gross rent set aside monthly for capital expenditure replacements.

The Full Suite of Outputs

Cash Flow — Monthly and Annual

True net cash flow: gross rent minus vacancy minus all operating expenses minus debt service. The complete formula, not the simplified version. This is what the property actually contributes to your income — or costs you — each month.

Cash-on-Cash Return

Annual net cash flow divided by total cash invested (down payment plus closing costs). Cash-on-cash return measures the efficiency of your capital deployment and is the most relevant return metric for leveraged buy-and-hold investing. Target 8–12% in most markets.

Cap Rate

Annual NOI divided by purchase price. The property's income performance independent of financing — the metric used to compare properties across different financing structures and to evaluate whether the asking price reflects the income the property produces.

Monthly NOI

Gross income minus operating expenses, before debt service. NOI is the income the asset generates as a standalone investment. This is the number DSCR lenders underwrite against.

Effective Monthly Rent, Total Monthly Expenses, and Mortgage

The calculator breaks down your total monthly outflow into its components: effective rent after vacancy, expenses category by category, and your mortgage payment separately. This breakdown helps you identify which costs are consuming the most margin and where optimization opportunities exist.

Quick-Screen Rules: 1%, 2%, 50%, and 70%

The calculator also evaluates your deal against the most widely used quick-screen rules in real estate investing:

1% Rule — does the monthly rent equal or exceed 1% of the purchase price? A property priced at $150,000 needs $1,500/month in rent to pass. The 1% rule is a rough screening filter, not a complete analysis, but it quickly eliminates properties that cannot generate meaningful cash flow at their price point.

2% Rule — a stricter screen used primarily in higher-yield markets. Difficult to find at current price levels in most major metros, but still useful as a comparison point.

50% Rule — a quick cash flow estimate: assume operating expenses equal 50% of gross rent, subtract your mortgage payment, and the remainder is estimated cash flow. Useful for screening before running a full analysis.

70% Rule — the classic wholesaler and flipper acquisition screen: the maximum offer should be no more than 70% of ARV minus repairs. Included in the rental analysis because it helps buy-and-hold investors who are also evaluating BRRRR or mixed-exit strategies.

Using the Calculator Across Your Investment Criteria

Every investor should have minimum return thresholds for buy-and-hold acquisitions. For example: minimum $200/month cash flow per unit, minimum 8% cash-on-cash return, minimum 6% cap rate in current rate environment. The Rental Property Calculator lets you apply those thresholds to every property consistently.

Properties that meet all three thresholds go to full due diligence. Properties that fail one or more either require a lower purchase price to work or are passed without further time investment. This discipline — applied consistently through a structured calculator — is what builds a portfolio of properties that actually perform.

Model Your Offer, Not Just the Listing Price

Before you enter a deal at the asking price, use the calculator to determine what price the property needs to trade at to meet your return thresholds. If the asking price is $225,000 but the property only hits your cash-on-cash target at $195,000, you have a data-grounded negotiating anchor.

Run the analysis at asking price. Then run it at your target offer. The difference between those two analyses is your negotiating mandate.

Open the Rental Property Calculator and run your next buy-and-hold target through the complete analysis. Available to Core and Pro members. Start your 7-day free trial today.