Investment Property Cash Flow Calculator
Analyze rental property cash flow including mortgage, taxes, insurance, vacancy, and management fees.
See your monthly and annual net income.
Rental property cash flow measures the actual money left in your pocket each month after collecting rent and paying all property-related expenses. Positive cash flow means the property is paying you; negative cash flow means you are subsidizing the property.
Core formula:
Monthly Cash Flow = Effective Gross Income − Total Monthly Expenses
Effective Gross Income (EGI) = Gross Rent × (1 − Vacancy Rate)
Typical expense categories:
| Expense | Typical Amount |
|---|---|
| Mortgage (P&I) | Based on loan terms |
| Property taxes | 1–2% of value per year |
| Landlord insurance | 0.5–1% of value per year |
| Vacancy allowance | 5–10% of gross rent |
| Property management | 8–12% of gross rent |
| Maintenance reserve | 5–10% of gross rent |
| CapEx reserve (big repairs) | 5–10% of gross rent |
| HOA fees | As applicable |
Maintenance and CapEx are two separate lines, and the second one is the one that gets skipped. Maintenance is the leaking tap and the annual boiler service. CapEx is the roof, the furnace, the windows and the kitchen: items that fail once every fifteen or twenty years and cost five figures when they do. Neither shows up in a given month, which is exactly why a property looks like it cash-flows until the year it does not.
Key performance metrics:
Cash-on-Cash Return = (Annual Cash Flow / Total Cash Invested) × 100
Cap Rate = (Annual Net Operating Income / Property Value) × 100
Gross Rent Multiplier (GRM) = Property Price / Annual Gross Rent
Worked example: $300,000 property, $2,400/month rent, $50,000 down payment, $1,650/month mortgage.
- EGI (7% vacancy) = $2,400 × 0.93 = $2,232
- Expenses: $1,650 (mortgage) + $250 (taxes) + $100 (insurance) + $192 (management, 8%) + $120 (maintenance, 5%) + $80 (CapEx, 3.33%) = $2,392
- Monthly cash flow = $2,232 − $2,392 = −$160/month (slight negative)
- Cash-on-cash return = (−$1,920 / $50,000) = −3.8% (this property needs higher rent or lower price)
Push the reserves to a fuller 5% each and the expenses rise to $2,432, taking the monthly figure to −$200 and the cash-on-cash return to −4.8%. That is the honest number, and it is the one most listings quietly leave out.
The 1% Rule of thumb: Monthly rent should be at least 1% of purchase price for positive cash flow to be likely. $300,000 property should rent for at least $3,000/month by this rule. This is harder to achieve in high-cost markets, and in those areas investors rely on appreciation rather than cash flow.
Beginner pitfall: Many first-time investors forget vacancy, maintenance, and CapEx reserves. A property that appears to cash flow $400/month “on paper” can easily turn negative when a roof, HVAC, or tenant turnover occurs.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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