What GRM tells you
GRM answers a simple question: how many years of gross rent does the price represent? A building priced at 10 times its annual rent has a GRM of 10. Because it uses gross rent rather than net income, you can calculate it from a listing sheet in seconds, before you have seen an expense statement.
That speed is also its limit. GRM ignores vacancy, operating expenses and other income, so two buildings with the same GRM can produce very different net income. It works best as a first filter and as a cross-check on a cap-rate valuation, not as the basis for an offer.
The formula in both directions
To find the multiplier, divide the purchase price by gross annual rent. To estimate value, turn it around: multiply gross annual rent by a market GRM drawn from comparable sales.
- GRM = price ÷ gross annual rent
- Estimated value = gross annual rent × market GRM
- Gross annual rent means scheduled rent from all units for twelve months, before vacancy and expenses.
A worked example
A building listed at $1,500,000 collects $150,000 a year in rent. Its GRM is $1,500,000 ÷ $150,000 = 10.
Now suppose three similar buildings nearby sold at GRMs of 9, 10 and 11. Multiplying $150,000 by that range suggests values between $1,350,000 and $1,650,000. If the listing sits in the middle of the range, the next step is to confirm that its expenses are in line with the comparables, since a building with owner-paid utilities or high taxes deserves a lower multiplier.
How to read the result
A lower GRM means you are paying less for each dollar of rent, which can signal a better buy or a building with higher expenses, more risk or more work ahead. A higher GRM usually reflects a stronger location, newer construction, tenant-paid utilities or rents well below market that a buyer expects to raise.
GRM is only meaningful against buildings of similar size, age and expense structure in the same market. Comparing a GRM from one city with another, or a 6-unit building with a 60-unit building, tells you little.
Common mistakes
Keep these in mind before relying on a multiplier.
- Mixing monthly and annual rent. Some markets quote GRM on monthly rent, which produces a number twelve times larger. This calculator uses annual rent.
- Using projected or market rents for one property and actual rents for the comparables.
- Treating GRM as a substitute for NOI when expenses differ between buildings.
- Ignoring vacancy: a half-empty building and a full one can show the same scheduled rent.