How this GRM calculator works
Gross rent multiplier is how many years of gross rent it takes to equal the purchase price. It is the fastest screen in rental investing: two numbers from the listing, one division, and you know roughly where a property sits before you open a spreadsheet.
The calculator divides price by annual gross income and shows the result three ways: as a GRM, as monthly rent divided by price (the figure behind the 1% rule), and as a gross yield. Set a target GRM and it solves for the price the rent supports and the rent the asking price would need.
Because GRM skips expenses, the calculator also shows what the ratio implies if the property's costs are typical: collected rent after vacancy, operating expenses at a percentage you can change, and the resulting cap rate. That bridge is what makes a GRM useful instead of just fast.
The gross rent multiplier formula
GRM = purchase price / annual gross rent
Gross rent is gross income: the scheduled rent at full occupancy plus recurring other income, before vacancy and before any expense. That is what separates GRM from cap rate, which divides net operating income, the rent left after expenses, by price.
Using the default property: $500,000 divided by $48,000 of annual rent ($4,000 a month) is a GRM of 10.4. Monthly rent is 0.80% of price, under the 1% rule. Gross yield is 9.6%.
At a target GRM of 8, that rent supports a price of $384,000, $116,000 below asking. Or, to justify $500,000 at a GRM of 8, rent would need to be $5,208.
With 5% vacancy and expenses at 36% of collected rent, the implied NOI is $29,184 and the implied cap rate is 5.8%. The formula guide works through the arithmetic and the monthly variant.
What is a good GRM?
A good GRM is at or below what comparable rentals in the same market have sold for. Lower means more rent per dollar of price. Most US residential rentals trade between 8 and 12. Under 8 is cash-flow territory. Over 12 is an appreciation market.
| GRM | Rent as % of price | Implied cap rate | Read as |
|---|---|---|---|
| 6x | 1.39% | 10.1% | Very low. Cheap markets, rough stock, or check the rent. |
| 8x | 1.04% | 7.6% | Low. The 1% rule. Cash flows with a normal loan. |
| 10x | 0.83% | 6.1% | Typical. Most metros. Thin cash flow at today's rates. |
| 12x | 0.69% | 5.1% | High. Appreciation markets. Needs a big down payment. |
| 16x | 0.52% | 3.8% | Very high. Coastal pricing. Income is a small part of the return. |
Implied cap rates assume 5% vacancy and a 36% expense ratio. Each GRM has its own page with the rent and price behind it: see what a GRM of 8 means or the guide to what counts as a good GRM.
Where GRM breaks
GRM treats every dollar of rent as equal. It is not. A condo with $800 in monthly dues and a house with none can have the same GRM while the condo's cap rate is two points lower. A property in a 2.2% property tax state and one in a 0.6% state look identical on GRM and are 1.6 cap rate points apart on $500,000.
So GRM works for sorting similar properties in one market and fails for comparing across markets or property types. Use it to build a short list, then underwrite the short list on expenses. GRM vs cap rate covers when the shortcut is safe.
What GRM does not reflect
Financing. GRM describes the property before any loan, so it says nothing about leverage or the debt service coverage ratio a lender will compute. Under typical expenses a GRM of 8 or lower usually carries a 75% loan at today's rates with room; a GRM of 12 usually does not cover the payment. The multiplier hints at which, and the full statement decides.
The exit. GRM prices this year's rent and ignores terminal value, what the property will be worth when you sell, which for most leveraged rentals is the largest cash flow in the investment. A discounted cash flow analysis captures it, and GRM is the compressed one-year version of that analysis. Use the multiplier to decide which properties deserve the full model.
GRM and the 1% rule
The 1% rule says monthly rent should be at least 1% of price. That is a GRM of 8.3 in different units. Under typical expenses it lands near a 7.3% cap rate, which is roughly where a property covers a 30-year loan at today's rates with 25% down. The rule was easy to meet in 2012 and is rare in most metros now. The 1% rule guide covers what replaced it.