50% Rule Calculator
Rule of thumb: operating expenses ≈ 50% of gross rent. Quick NOI estimator.
Result
Estimated cash flow
$50/mo
Positive cash flow.
- Gross rent (monthly)$2,500
- Estimated opex (50%)$1,250
- Estimated NOI (monthly)$1,250
- Mortgage P&I$1,200
- Cash flow (monthly)$50
- Annual cash flow$600
Step-by-step
- Estimated opex = 50% × 2,500 = $1,250/mo.
- Estimated NOI = 2,500 − 1,250 = $1,250/mo.
- Cash flow = NOI − mortgage = 1,250 − 1,200 = $50/mo.
How to use this calculator
- Enter gross monthly rent.
- Enter monthly mortgage P&I.
- Read estimated cash flow.
About this calculator
The 50% rule says total operating expenses average 50% of gross rent over the long run. This is rough but surprisingly stable across many markets: taxes (1-2% of price annually), insurance, vacancy (5-8%), maintenance (5-10% of rent), management (8-12% if outsourced), capex reserve (5-10%). Use to quickly estimate NOI without itemizing every expense.
Frequently asked
No — it's an average. New construction with no capex coming has lower opex; old properties with high taxes have more. Treat as a starting estimate, refine with actual numbers.
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