Real Estate Calculator: method, checked example and practical limits
Measure a property's net operating income, cap rate, cash flow and cash-on-cash return. Cap rate evaluates unlevered operating income against price, while cash flow also reflects the chosen borrowing terms.
Inputs used by this calculator
Real Estate Calculator uses the fields below. The starting values reproduce the page example; replace them with values from the same units and time period before using the result.
| Input | Starting example | Accepted value | How it is used |
|---|---|---|---|
| Purchase price ($) | 350,000 | 0.01 to 1000000000000 | Supplies the purchase price ($) quantity used by the published equation or result breakdown. |
| Down payment ($) | 70,000 | 0 to 1000000000000 | Supplies the down payment ($) quantity used by the published equation or result breakdown. |
| Monthly rent ($) | 3,000 | 0 to 1000000000 | Supplies the monthly rent ($) quantity used by the published equation or result breakdown. |
| Vacancy (%) | 5 | 0 to 100 | Supplies the vacancy (%) quantity used by the published equation or result breakdown. |
| Monthly operating expenses ($) | 900 | 0 to 1000000000 | Supplies the monthly operating expenses ($) quantity used by the published equation or result breakdown. |
| Monthly mortgage payment ($) | 1,700 | 0 to 1000000000 | Supplies the monthly mortgage payment ($) quantity used by the published equation or result breakdown. |
| Closing and initial costs ($) | 10,000 | 0 to 1000000000 | Supplies the closing and initial costs ($) quantity used by the published equation or result breakdown. |
Inputs and measurement conventions
The quantities used on this page are Purchase price ($), Down payment ($), Monthly rent ($), Vacancy (%), Monthly operating expenses ($), Monthly mortgage payment ($), Closing and initial costs ($). Start with values for the same situation and read the units attached to each field. The field reference below shows supported choices and numerical limits.
Debt service is excluded from NOI. Major capital repairs, sale costs and income taxes need separate treatment to avoid overstating returns.
Method and equation
Reduce rent for vacancy, subtract operating expenses for NOI, then subtract mortgage payments for the financing cash-flow view.
Real Estate Calculator uses the following stated relationship: NOI=effective rent−operating expenses; cap rate=NOI/price. Its assumptions determine which question the answer can resolve.
NOI=effective rent−operating expenses; cap rate=NOI/priceWorked calculation with the starting values
Purchase price ($): 350000; Down payment ($): 70000; Monthly rent ($): 3000; Vacancy (%): 5; Monthly operating expenses ($): 900; Monthly mortgage payment ($): 1700; Closing and initial costs ($): 10000. These starting values give 3,000 annual pre-tax cash flow. The calculation breakdown is Effective gross income: 34,200; NOI: 23,400; Cap rate: 6.685714285714285%; Cash-on-cash return: 3.75%.
$3,000 monthly rent is adjusted for vacancy and operating costs before mortgage cash flow is shown.
Reading the answer
Cap rate evaluates unlevered operating income against price, while cash flow also reflects the chosen borrowing terms.
Effective gross income: 34,200; NOI: 23,400; Cap rate: 6.685714285714285%; Cash-on-cash return: 3.75%. These intermediate quantities make the stated Real Estate Calculator model inspectable; they should be read together with the main answer rather than treated as independent guarantees.
Common errors and model boundaries
Debt service is excluded from NOI. Major capital repairs, sale costs and income taxes need separate treatment to avoid overstating returns.
Income taxes, appreciation, selling costs, reserves and irregular capital expenditures need separate scenario analysis.
Independent verification and next decision
Yes. A property's operating income can be positive while its financing payment exceeds that income.
For the Real Estate Calculator method, compare NOI=effective rent−operating expenses; cap rate=NOI/price with the starting inputs and the calculation table. The linked Consumer Financial Protection Bureau: consumer tools and Investor.gov (SEC): compound interest calculator references identify the relevant definitions, conventions or domain limitations. Retain intermediate precision when comparing a manually worked answer.
Real Estate Calculator worked-example ledger
| Quantity | Example value | Role |
|---|---|---|
| Purchase price ($) | 350000 | Entered assumption |
| Down payment ($) | 70000 | Entered assumption |
| Monthly rent ($) | 3000 | Entered assumption |
| Vacancy (%) | 5 | Entered assumption |
| Monthly operating expenses ($) | 900 | Entered assumption |
| Monthly mortgage payment ($) | 1700 | Entered assumption |
| Closing and initial costs ($) | 10000 | Entered assumption |
| Main answer | 3,000 annual pre-tax cash flow | Calculated from the starting inputs |
| Effective gross income | 34,200 | Intermediate or contextual output |
| NOI | 23,400 | Intermediate or contextual output |
| Cap rate | 6.685714285714285% | Intermediate or contextual output |
| Cash-on-cash return | 3.75% | Intermediate or contextual output |
Frequently asked questions
Can positive NOI coexist with negative cash flow?
Yes. A property's operating income can be positive while its financing payment exceeds that income.
Which relationship does the Real Estate Calculator use?
Reduce rent for vacancy, subtract operating expenses for NOI, then subtract mortgage payments for the financing cash-flow view. The displayed relationship is NOI=effective rent−operating expenses; cap rate=NOI/price.
What do the starting values produce in the Real Estate Calculator?
Purchase price ($): 350000; Down payment ($): 70000; Monthly rent ($): 3000; Vacancy (%): 5; Monthly operating expenses ($): 900; Monthly mortgage payment ($): 1700; Closing and initial costs ($): 10000. These starting values give 3,000 annual pre-tax cash flow. The calculation breakdown is Effective gross income: 34,200; NOI: 23,400; Cap rate: 6.685714285714285%; Cash-on-cash return: 3.75%.
How should I interpret this Real Estate Calculator answer?
Cap rate evaluates unlevered operating income against price, while cash flow also reflects the chosen borrowing terms.
Which input mistake most affects the Real Estate Calculator?
Debt service is excluded from NOI. Major capital repairs, sale costs and income taxes need separate treatment to avoid overstating returns.
What is outside this Real Estate Calculator model?
Income taxes, appreciation, selling costs, reserves and irregular capital expenditures need separate scenario analysis.
What to keep in mind
Income taxes, appreciation, selling costs, reserves and irregular capital expenditures need separate scenario analysis.
Results are rounded for display in US format, with money in dollars and cents; CSV exports keep full calculation precision. This is a calculation summary, not an official certificate.