50% Rule (Real Estate)

Real Estate Investing

Updated Apr 2026 • Has calculator

A rule of thumb estimating that approximately 50% of a rental property's gross rent is consumed by operating expenses — excluding mortgage payments.

What is 50% Rule?

The 50% rule states that operating expenses for a rental property — including property taxes, insurance, maintenance, property management, vacancy allowance, and capital expenditure reserves — will consume roughly half of gross rents over time. The remaining half (estimated NOI) is available to service debt and generate profit. While the actual percentage varies by property age, condition, and market, the 50% rule provides a quick way to estimate NOI without a full expense pro forma. Newer properties or those managed efficiently may come in at 40–45%; older properties with deferred maintenance or high tax burdens may exceed 50%.

Formula

Estimated NOI = Gross Annual Rent × 50%

Worked Example

2024

Step 1 3 units × $1,200/mo × 12 = $43,200 gross annual rent

Step 2 Estimated operating expenses (50% rule): $43,200 × 50% = $21,600

Step 3 Estimated NOI = $43,200 − $21,600 = $21,600

Step 4 → With actual expenses tracked at $19,800, rule over-estimated by only $1,800

Step 5 → Cap rate at $360,000 purchase price: $21,600 / $360,000 = 6.00%

Source: Investopedia — 50% Rule in Real Estate (2024-01-01)

Calculate 50% Rule

Gross Annual Rent ($)

Total annual rent income before any expenses or vacancies

Estimated NOI (50% Rule)

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Not investment advice.

How to Interpret 50% Rule

< 8000

Low estimated NOI — thin margins at typical leverage

8000 – 20000

Moderate NOI — may support a mortgage if price is right

20000 – 50000

Solid NOI — healthy cash flow potential at moderate prices

> 50000

Strong NOI — large or multi-unit property with good income

📚 Advanced Real Estate — Complete the path

Sources

Investopedia — 50% Rule in Real Estate