Professional appraisers use three distinct methodologies to value real estate. Each approach answers the same question — what is this property worth? — but from a different angle. Understanding when to apply each method, and how to run the numbers yourself, gives you a significant edge as an investor, agent, or buyer navigating any transaction.
Most valuations use more than one approach as a cross-check. When multiple methods converge on a similar value, confidence is high. When they diverge significantly, that's a signal to dig deeper into why.
The two most common income approach formulas are direct capitalization (using cap rate) and gross rent multiplier (GRM).
Direct Capitalization
Gross Rent Multiplier (GRM)
GRM is a faster, less precise version of the income approach. It divides the purchase price by annual gross rent. A property selling for $220,000 with $24,000 in gross annual rent has a GRM of 9.2. Lower GRM = better yield. Useful for quick screening but doesn't account for expense differences between properties.
The adjustment process is what separates a rigorous comp analysis from a superficial one. You identify properties sold within 90 days in the same market, then make dollar adjustments for every meaningful difference: square footage, bedroom/bathroom count, lot size, garage, condition, features, and location within the neighborhood.
Key principle: Adjustments flow from the comparable to the subject. If the comp has a feature the subject doesn't — subtract from the comp's value. If the subject has something the comp doesn't — add to the comp's value. You're adjusting what the comparable would have sold for if it matched the subject property.
Depreciation in the cost approach includes physical deterioration (wear and tear), functional obsolescence (outdated floor plan, dated features), and external obsolescence (factors outside the property — industrial neighbor, declining area). An older property may have significant depreciation applied even if it's been well-maintained.
Which Method Should You Use?
- Buying a rental property: Lead with the income approach. What does the NOI support at market cap rates? That's your ceiling.
- Buying a primary residence: Sales comparison is primary. What have similar homes sold for recently?
- Buying new construction or a unique property: Cost approach provides the most reliable floor on value.
- Cross-checking any deal: Run all three when data is available. Agreement between methods = confidence. Divergence = do more digging.
Use the Property Value Estimator and Cap Rate Calculator to run income approach valuations, and the Price Per Square Foot Calculator to support your sales comparison analysis.