50% Rule Calculator

Free 50% rule calculator. Estimate a rental's operating expenses and cash flow fast by assuming expenses run about half of rent.

Est. expenses (50%)

$1,100

rule-of-thumb opex

Est. cash flow

-$300/mo

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What is 50% Rule?

The 50% rule assumes that, over time, a rental's operating expenses (taxes, insurance, maintenance, vacancy, management, capital repairs) average about half of the gross rent — before the mortgage.

It's a sanity check against optimistic pro formas: subtract half the rent for expenses, then the mortgage, and see if anything's left.

Formula

Estimated operating expenses = 50% × gross rent. Cash flow ≈ rent − (50% × rent) − mortgage payment.

How to read it

  • Whatever's left after 50% of rent and the mortgage payment is your rough monthly cash flow.
  • New construction or low-tax areas may run below 50%; old properties or high-tax states can run above it.
  • Use it to gut-check a deal, then replace the estimate with real numbers before you buy.

Frequently asked questions

Is the 50% rule accurate?
It's a rough average, not a precise figure. Actual expense ratios vary with property age, taxes, and management. Treat it as a fast reality check, then verify with itemized expenses.
Does the 50% rule include the mortgage?
No. The 50% covers operating expenses only. You subtract the mortgage payment separately to estimate cash flow.