Rental Property Cash Flow Calculator

Calculate monthly and annual cash flow after mortgage, expenses, and vacancy. Enter your numbers below — results update in real time.

Property Details

$
%

% of purchase price

%

Annual mortgage rate

years

Typically 15 or 30 years

$
$

HOA, insurance, management

%

% of time property is empty

Results

Monthly Mortgage

$1,596.73

Monthly Cash Flow

$3.27

Annual Cash Flow

$39.29

Cash-on-Cash Return

0.07%

Total ROI

0.07%

CoC > 8% — Excellent4–8% — Decent< 4% — Low

How to Calculate Rental Property Cash Flow

Cash flow is the net money you receive each month after paying all property-related expenses, including your mortgage.

Monthly Cash Flow Formula

Effective Rent − Monthly Expenses − Monthly Mortgage = Cash Flow

Effective Rent = Monthly Rent × (1 − Vacancy Rate)

Example: ($2,000 × 0.95) − $300 − $1,200 = $400/month

Always use effective rent (rent adjusted for vacancy) rather than asking rent. A 5% vacancy allowance is a conservative and commonly used rule of thumb.

Cash-on-Cash Return vs. Cap Rate

MetricIncludes financingBest used for
Cash-on-Cash ReturnYes — after mortgageComparing leveraged deals
Cap RateNo — unleveraged NOIComparing properties independently of financing
Gross YieldNo — gross rent onlyQuick market-level screening

What Is a Good Cash-on-Cash Return?

  • > 10% — Excellent. Strong cash-generating property relative to the equity deployed.
  • 8–10% — Very good. Beats most alternative investments on a cash basis.
  • 4–8% — Decent. Common in high-cost markets. May be justified with strong appreciation.
  • < 4% — Low. You are likely relying on appreciation, not income, to make the investment work.

Frequently Asked Questions

What is cash flow in rental property investing?
Cash flow is the money remaining each month after collecting rent and paying all expenses — mortgage, insurance, property management, HOA, and vacancy allowance. Positive cash flow means the property earns more than it costs to hold.
What is a good monthly cash flow for a rental property?
Many investors target at least $100–$200 per unit per month in net cash flow. However, the absolute number matters less than the cash-on-cash return relative to your down payment. A $300/month cash flow on a $30,000 investment is excellent; the same number on a $200,000 down payment is very weak.
What is cash-on-cash return?
Cash-on-cash return (CoC) is your annual pre-tax cash flow divided by the total cash you invested (typically the down payment plus closing costs). A CoC of 8% or more is generally considered strong for a leveraged rental property.
How does vacancy rate affect cash flow?
Vacancy reduces your effective rent. A 5% vacancy rate means the property sits empty for roughly 18 days per year. Always factor in vacancy — even in tight rental markets, tenant turnover and unit preparation create some downtime.
Should I include principal paydown in cash flow?
Standard cash flow analysis does not include principal paydown — it only considers cash in vs. cash out. Principal paydown builds equity but is not money in your pocket today. It is better treated as a separate component of total return alongside appreciation and tax benefits.