Purpose and steps
The Multifamily Rental Cash Flow Calculator validates every input, normalizes monthly and annual amounts, and calculates gross potential rent, vacancy, operating expenses, NOI, debt service, and DSCR from one consistent scenario.
- Confirm currency and monthly versus annual amounts. U.S. tax and loan models should be used within their stated scope.
- Prepare Property type, Number of units, Average monthly rent per unit, Vacancy allowance, Operating-expense ratio, Monthly mortgage payment. Defaults demonstrate the model rather than your personal circumstances.
- Check the headline result and its components. A key interpretation for this tool is: DSCR barely above 1 leaves little room for rent loss or repairs; a positive number alone is not a sufficient reserve.
- Compare the baseline with a changed scenario: The occupancy reference freezes current expenses; an exact break-even analysis would separate fixed and variable costs.
Input reference and units
These values reproduce the model’s demonstration. Replace them with your own records or measurements; they are not recommended targets.
On a small screen, swipe the table horizontally to see all columns.
| Parameter | Demonstration value | How to enter it |
|---|---|---|
| Property type | Duplex | Use the definition shown in the field label; keep this assumption consistent when comparing scenarios. |
| Number of units | 2 number | Use the definition shown in the field label; keep this assumption consistent when comparing scenarios. |
| Average monthly rent per unit | 1800 USD | Use dollars and the monthly or annual period stated in the field label; do not enter thousands of dollars. |
| Vacancy allowance | 5 % | Enter a percentage such as 6.5, not 0.065. The equation converts it to a decimal. |
| Operating-expense ratio | 40 % | Enter a percentage such as 6.5, not 0.065. The equation converts it to a decimal. |
| Monthly mortgage payment | 2000 USD | Use dollars and the monthly or annual period stated in the field label; do not enter thousands of dollars. |
Model-specific method
How this calculator produces its result
Potential rent G = units × average monthly rent × 12. Effective income E = G × (1−vacancy). NOI = E × (1−operating-expense ratio). Annual cash flow = NOI − annual debt service D; DSCR = NOI / D. The displayed occupancy reference uses current expenses plus D divided by G.
A cash-flow waterfall and scenario sensitivity
Income and costs form successive layers. Subtracting financing before computing NOI changes the definition and distorts cap-rate comparisons. Principal repayment uses cash but can also build equity, so a tax profit, operating profit and cash-flow result may legitimately differ.
Sensitivity analysis changes one assumption while keeping the others fixed. If yearly potential rent is G, a one-percentage-point vacancy increase directly reduces collected rent by G×0.01, before variable expense offsets. Combined stress scenarios are also important: vacancy, maintenance and borrowing costs can worsen together.
Effective income = potential income × (1 − vacancy) NOI = effective income − operating expenses Cash flow = NOI − debt service DSCR = NOI / debt service
- Potential income: before vacancy or collection loss
- NOI: net operating income before financing
- Debt service: contractual principal and interest payments
- Cash flow: money remaining after the modeled payments
Worked example
Two units at $1,800 monthly rent produce $43,200 potential income. At 5% vacancy and 40% expense ratio, NOI is $24,624. A $2,000 monthly mortgage costs $24,000 a year, leaving $624 annually or $52 monthly; DSCR is 1.026.
Reproduce the default scenario
This is a separate example, calculated using the exact engine on the tool page and the defaults in the input reference above. Health examples use metric units. Displayed rounding may differ from intermediate precision.
- Estimated monthly cash flow
- 52 USD
- Gross potential rent
- 43,200 USD
- Effective gross income
- 41,040 USD
- Operating expenses
- 16,416 USD
- Net operating income
- 24,624 USD
- Annual debt service
- 24,000 USD
- Annual cash flow
- 624 USD
- Debt-service coverage ratio
- 1.03
- Break-even occupancy
- 93.56%
Reading results without overstating them
- DSCR barely above 1 leaves little room for rent loss or repairs; a positive number alone is not a sufficient reserve.
- The occupancy reference freezes current expenses; an exact break-even analysis would separate fixed and variable costs.
Assumptions and exclusions
- A single average rent and expense ratio hide differences across units. Capital expenditure, management detail, rent concessions and tax are excluded.
Sources and content notes
Toolify describes the implemented algorithm and its assumptions. Sources below support the topic or applicable rules; they do not endorse this calculator. Examples are illustrative, and published rules take precedence over simplified estimates.
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