Rental Property Calculator Estimate cash flow, cap rate, and ROI for residential real estate — with financing, expenses, ...
Rental Property Calculator
Estimate cash flow, cap rate, and ROI for residential real estate — with financing, expenses, and tax considerations.
Gross Scheduled Income (GSI)** = Monthly Rent × 12
Effective Gross Income (EGI)** = GSI × (1 − Vacancy Rate)
Net Operating Income (NOI)** = EGI − Operating Expenses → *Does not include mortgage, depreciation, or capex*
Cap Rate** = NOI ÷ Purchase Price → Measures unleveraged return (all-cash purchase)
Cash-on-Cash ROI** = (NOI − Debt Service) ÷ Cash Invested → Measures leveraged return (with mortgage)
Example ($300K SFH, $2,200 rent, 5% vacancy, $1,500/mo expenses): • EGI = $26,400 × 0.95 = **$25,080** • NOI = $25,080 − $18,000 = **$7,080** • Cap Rate = $7,080 / $300,000 = **2.36%** → *Wait, too low!* → Correction: expenses should be ~$9,000/yr → NOI = $16,080 → **5.36% cap** ✅
⚠️ Avoid these dangerous deals:
- Cap rate < 4% in non-appreciation markets** — insufficient margin for error
- Cash flow < $100/mo/unit** — vulnerable to vacancy or repair spikes
- Expense ratio > 50%** (expenses ÷ EGI) → likely negative leverage
- Rent-to-income > 35%** — high tenant turnover risk
✅ Pro Tips**:
- Use the **1% Rule** as screening: Rent ≥ 1% of purchase price ($300K → $3,000/mo)
- Factor in **capex reserve** (5% of EGI) for roof, HVAC, etc.
- Model worst-case: 10% vacancy + $5K repair + 6 months rent loss
| Property | Price | Rent | Cap | Cash-on-Cash (20% down) |
|---|---|---|---|---|
| SF Home (Sun Belt) | $300K | $2,200 | 5.8% | 9.2% |
| Duplex (Midwest) | $400K | $2,800 | 6.2% | 10.1% |
| 4-Plex (Urban) | $650K | $4,800 | 5.6% | 8.7% |
📉 Expense Estimates (Annual)**:
- Property Tax: 0.8–1.8% of value
- Insurance: 0.3–0.5%
- Maintenance: 0.8–1.2%
- Capex Reserve: 0.5–1.0%
- Property Mgmt: 8–10% of rent
➡️ Cash Flow
“$2,200 rent, 5% vacancy, $1,250/mo expenses — what’s my net?”
➡️ Cap Rate & ROI
“$7K NOI on $300K purchase — what’s my cap? With $60K down — what’s cash-on-cash?”
➡️ Financing
Compare 20% vs. 25% down, 15 vs. 30 yr terms — see cash flow impact.
➡️ Exit Strategy
“3% appreciation for 5 years — how much equity? After 6% sale costs?”
Note: Uses 2025 avg. cap rates (4–7%), mortgage rates (6.5%), and expense norms. Does not include depreciation or tax effects (consult CPA).