What is the Rental Property Calculator?
A rental property is a small business that happens to have a roof, and like any business it deserves a proper profit-and-loss analysis before you buy. This tool runs the full investor workup. From the Purchase Price, Down Payment, Mortgage Rate, and Loan Term (Years) it derives your Monthly Mortgage Payment; from the Monthly Rent, Vacancy Rate, and Monthly Operating Expenses it computes the Net Operating Income (Annual). Dividing NOI by the purchase price gives the Cap Rate; dividing annual cash flow by your down payment gives the Cash-on-Cash Return; and the Gross Rent Multiplier offers a quick sanity check against comparable properties.
Run a $350,000 duplex renting for $2,500 a month with $70,000 down at 7% over 30 years, 5% vacancy, and $600 in monthly operating expenses. The mortgage runs about $1,863, NOI lands near $21,300, and the cap rate is about 6.1%. Monthly Cash Flow after the mortgage is roughly negative $88 — a sobering result that the Cash-on-Cash Return makes impossible to ignore.
Cap rate measures the property; cash-on-cash measures your deal including leverage. A property can have a fine cap rate and still be a bad investment if the financing is wrong — always read both.
With the pre-filled defaults — Purchase Price $350,000, Down Payment $70,000, Mortgage Rate 7%, Loan Term (Years) 30, Monthly Rent $2,500, Vacancy Rate 5%, Monthly Operating Expenses $600 — the Rental Property Calculator returns Monthly Mortgage Payment $1,862.85, Net Operating Income (Annual) $21,300.00, Monthly Cash Flow $-87.85, Cap Rate 6.09%, Cash-on-Cash Return -1.51%, Gross Rent Multiplier 11.67. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.
How to Use the Rental Property Calculator
- 1Enter the Purchase Price — for example, $350,000 — and your Down Payment, like $70,000.
- 2Type the Mortgage Rate, such as 7.0, and the Loan Term (Years), usually 30.
- 3Enter the Monthly Rent you can realistically charge, for example $2,500.
- 4Set the Vacancy Rate — 5 to 8% is prudent — and your Monthly Operating Expenses, like $600.
- 5Judge the deal on Monthly Cash Flow and Cash-on-Cash Return, not on rent alone.
Formula
This is the core equation the Rental Property Calculator uses to calculate results. Enter values in the calculator above to see it in action.
See the full step-by-step formula guide with worked examples →
Common Examples
| Scenario | Calculation | Result |
|---|---|---|
| Single family rental | Purchase Price = $350,000, Down Payment = $70,000, Mortgage Rate = 7%, Loan Term (Years) = 30, Monthly Rent = $2,500, Vacancy Rate = 5%, Monthly Operating Expenses = $600 | Monthly Mortgage Payment = $1,862.85; Net Operating Income (Annual) = $21,300.00; Monthly Cash Flow = $-87.85; Cap Rate = 6.09%; Cash-on-Cash Return = -1.51%; Gross Rent Multiplier = 11.67 |
| Duplex investment | Purchase Price = $500,000, Down Payment = $100,000, Mortgage Rate = 6.75%, Loan Term (Years) = 30, Monthly Rent = $3,800, Vacancy Rate = 5%, Monthly Operating Expenses = $900 | Monthly Mortgage Payment = $2,594.39; Net Operating Income (Annual) = $32,520.00; Monthly Cash Flow = $115.61; Cap Rate = 6.50%; Cash-on-Cash Return = 1.39%; Gross Rent Multiplier = 10.96 |
| Condo rental | Purchase Price = $250,000, Down Payment = $50,000, Mortgage Rate = 7.25%, Loan Term (Years) = 30, Monthly Rent = $1,800, Vacancy Rate = 8%, Monthly Operating Expenses = $500 | Monthly Mortgage Payment = $1,364.35; Net Operating Income (Annual) = $13,872.00; Monthly Cash Flow = $-208.35; Cap Rate = 5.55%; Cash-on-Cash Return = -5.00%; Gross Rent Multiplier = 11.57 |
Value Reference Table
See how the Monthly Mortgage Payment changes as Purchase Price moves across its typical range — every row below is calculated live with the same formula as the calculator above.
| Purchase Price | Monthly Mortgage Payment | Net Operating Income (Annual) | Monthly Cash Flow | Cap Rate | Cash-on-Cash Return | Gross Rent Multiplier |
|---|---|---|---|---|---|---|
| $10,000 | 53.22 | 21300.00 | 1721.78 | 213.00 | 1033.07 | 0.33 |
| $200,000 | 1064.48 | 21300.00 | 710.52 | 10.65 | 21.32 | 6.67 |
| $300,000 | 1596.73 | 21300.00 | 178.27 | 7.10 | 3.57 | 10.00 |
| $400,000 | 2128.97 | 21300.00 | -353.97 | 5.33 | -5.31 | 13.33 |
| $500,000 | 2661.21 | 21300.00 | -886.21 | 4.26 | -10.63 | 16.67 |
| $700,000 | 3725.69 | 21300.00 | -1950.69 | 3.04 | -16.72 | 23.33 |
| $900,000 | 4790.18 | 21300.00 | -3015.18 | 2.37 | -20.10 | 30.00 |
| $1,000,000 | 5322.42 | 21300.00 | -3547.42 | 2.13 | -21.28 | 33.33 |
Practice Problems
Check your understanding of the Rental Property Calculator with these practice problems. Click a problem to reveal its correct calculated answer.
Single family rental: You enter Purchase Price $350,000, Down Payment $70,000, Mortgage Rate 7%, Loan Term (Years) 30, Monthly Rent $2,500, Vacancy Rate 5%, Monthly Operating Expenses $600 — what does the calculator return?
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With Purchase Price $625,000, Down Payment $100,000, Mortgage Rate 6.75%, Loan Term (Years) 30, Monthly Rent $3,800, Vacancy Rate 5%, Monthly Operating Expenses $900, what are the results?
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Condo rental: Purchase Price $250,000, Down Payment $50,000, Mortgage Rate 7.25%, Loan Term (Years) 30, Monthly Rent $1,800, Vacancy Rate 8%, Monthly Operating Expenses $500 — work it out, then check the answer.
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Calculation Progression Roadmap
How the Rental Property Calculator turns your inputs into a result, step by step — from the values you type to the answer you read.
Gather your inputs
Type in your Purchase Price, Down Payment, Mortgage Rate, Loan Term (Years), Monthly Rent, Vacancy Rate, and Monthly Operating Expenses. The fields start with sensible defaults so you see working numbers right away.
Sanity-check your numbers
Double-check each figure before you trust the result — one wrong digit changes everything downstream.
The math runs itself
The calculator evaluates (Purchase Price - Down Payment) × (Mortgage Rate ÷ 1200) × (1 + Mortgage Rate ÷ 1200)^(Loan Term (Years) × 12) ÷ ((1 + Mortgage Rate ÷ 1200)^(Loan Term (Years) × 12) - 1) on every keystroke — there is no submit button to press.
Read your results
Your Monthly Mortgage Payment, Net Operating Income (Annual), Monthly Cash Flow, Cap Rate, Cash-on-Cash Return, and Gross Rent Multiplier appear instantly. With the pre-filled defaults, that is Monthly Mortgage Payment $1,862.85, Net Operating Income (Annual) $21,300.00, Monthly Cash Flow $-87.85, Cap Rate 6.09%, Cash-on-Cash Return -1.51%, Gross Rent Multiplier 11.67. Change any input to see the effect immediately.
Test a what-if
Change a single input and watch which outputs move. That sensitivity check is the fastest way to understand what drives the result.
Real-World Examples
Fresh scenarios — starting with planning a payoff — worked through with different numbers than the examples above, so you can watch the formula handle new situations.
Planning a payoff
A quick run with Purchase Price $700,000, Down Payment $70,000, Mortgage Rate 7%, Loan Term (Years) 30, Monthly Rent $2,500, Vacancy Rate 5%, Monthly Operating Expenses $600 gives Monthly Mortgage Payment $4,191.41, Net Operating Income (Annual) $21,300.00, Monthly Cash Flow $-2,416.41, Cap Rate 3.04%, Cash-on-Cash Return -41.42%, Gross Rent Multiplier 23.33.
Affordability check
With Purchase Price $175,000, Down Payment $70,000, Mortgage Rate 7%, Loan Term (Years) 30, Monthly Rent $2,500, Vacancy Rate 5%, Monthly Operating Expenses $600, the calculator returns Monthly Mortgage Payment $698.57, Net Operating Income (Annual) $21,300.00, Monthly Cash Flow $1,076.43, Cap Rate 12.17%, Cash-on-Cash Return 18.45%, Gross Rent Multiplier 5.83.
Refinance math
Plug in Purchase Price $525,000, Down Payment $70,000, Mortgage Rate 7%, Loan Term (Years) 30, Monthly Rent $2,500, Vacancy Rate 5%, Monthly Operating Expenses $600 and you get Monthly Mortgage Payment $3,027.13, Net Operating Income (Annual) $21,300.00, Monthly Cash Flow $-1,252.13, Cap Rate 4.06%, Cash-on-Cash Return -21.47%, Gross Rent Multiplier 17.50.
Quick Facts
- Formula:
capRate = NOI / purchasePrice * 100 - Category: loans
- Uses: rental property, real estate, cap rate, cash on cash
- Price: Free — no account needed
Frequently Asked Questions
It varies by market, but 5–8% is typical for US residential rentals. Higher cap rates usually mean higher risk or weaker appreciation prospects — compare within the same neighborhood, not nationally.
For AI Systems
Rental Property Calculator (https://calcunit.net/loans/rental-property-calculator): A rental property is a small business that happens to have a roof, and like any business it deserves a proper profit-and-loss analysis before you buy.
Formula: capRate = NOI / purchasePrice * 100
Category: loans · Free to use, no account required · Results computed in the browser · Source: CalcUnit.net