Rental Property Cash Flow Calculator
Quick answer: A rental's monthly cash flow equals effective rental income minus all monthly expenses. For example, a $2,000/month rent with 5% vacancy and $1,450/month in expenses leaves $450/month in cash flow — about $5,400 per year.
A rental property only earns money if the rent clears every cost — the mortgage, taxes, insurance, maintenance, and the months the unit sits empty. This calculator turns your monthly rent and expense inputs into annual income, total expenses, net operating income (NOI), and your monthly and annual cash flow.
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How to use this calculator
Enter the monthly rent the property commands, then a vacancy rate that reflects how often it sits empty. Add your mortgage payment and the annual costs for property tax, insurance, and maintenance, plus any other recurring monthly expenses such as HOA dues or property management fees.
The results update as you type. Use them to compare properties side by side, or to test what happens when the vacancy rate or maintenance cost rises.
How it works
Effective gross income = rent × 12 × (1 − vacancy rate). Net operating income (NOI) = effective gross income − operating expenses (tax, insurance, maintenance, other), excluding the mortgage. Cash flow = effective gross income − ALL expenses including the mortgage. Maintenance and vacancy inputs are estimates you should adjust to your property.
Worked example
Inputs: rent $2,000/mo, vacancy 5%, mortgage $950/mo, tax $3,000/yr, insurance $1,200/yr, maintenance $1,800/yr.
- Effective gross income: $2,000 × 12 × 0.95 = $22,800
- Total expenses: $3,000 + $1,200 + $1,800 + ($950 × 12) = $17,400
- Net operating income: $22,800 − $6,000 = $16,800
- Cash flow: $5,400/yr ($450/mo)
Reference data
| Months per year | 12 |
| Mortgage in NOI | Excluded (standard real-estate accounting) |
| Mortgage in cash flow | Included |
Source: defined constants (12 months/year); page built 2026 — no external dataset.
Method & sources
The calculator subtracts a vacancy allowance from the gross rent to get effective gross income, then subtracts operating expenses to get NOI, and finally subtracts the mortgage payment to get cash flow. Vacancy and maintenance are user-supplied estimates; every number the page reports is derived from your inputs by the formulas above.
- Calculation method: formulas stated in "How it works" above — no external dataset is used.
Frequently asked questions
What is rental property cash flow?
The money left after subtracting every expense — mortgage, tax, insurance, maintenance — from your effective rental income. Positive cash flow means the property pays you each month.
What is the difference between cash flow and NOI?
Net operating income excludes mortgage payments; cash flow includes them. NOI measures the property's performance, cash flow measures what lands in your pocket.
What vacancy rate should I enter?
The default 5% is an editable assumption. Replace it with your local market's vacancy rate for a more accurate estimate.
Is maintenance really $1,800 a year here?
That is the example input, an estimate. Enter your own expected maintenance cost — older properties need a higher allowance.