50% rule

A shortcut estimate: about half of gross rent goes to operating expenses (not including mortgage). Useful for quick napkin math on rentals.

Investment terms · Updated September 2026

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Part 1 of 4

Why a seller cares

The 50% rule says about half of gross rent goes to expenses before the mortgage. When an investor screens your rental, they assume it whatever your records say, and your NOI figure gets compared to it.

Part 2 of 4

A simple example

Your duplex grosses $27,000. The 50% rule assumes $13,500 of expenses, leaving $13,500 of NOI; your records show $16,000.

50% rule: a simple example
The estimateThe NOI it produces
The 50% rule$13,500
Your actual records$16,000
What the buyer underwritesSomewhere between, closer to yours if the records are good

The 50% rule is the buyer's default. Real records move them off it.

Part 3 of 4

What people get wrong

That the rule includes the mortgage. It does not; the 50% is operating expenses only.

Part 4 of 4 · where to read next

Where it appears in the sale

What a definition is, and what it isn't

Keighbor is a software company, not a law firm, brokerage, or tax adviser. This is general information, not legal, tax, financial, or real estate advice about your sale. Your situation may differ. Before acting on a contract, disclosure, title, tax, or pricing question, ask an appropriately licensed professional in your state.

Written and researched by Keighbor Research · drawn from the reference glossary · how we research and check what we publish

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