GRM Calculator
Work out a property's gross rent multiplier from its price and gross rent, the price a target GRM supports, and how it compares with the cap rate. Type the rent as a month's or a year's figure; the result shows the annual and the monthly GRM, and the cap rate when you add the expenses, with the working.
Your numbers
Asking price, offer or sale price.
All the rent the property brings in before any expenses or vacancy, every unit.
Optional, for the cap rate. A percent of the gross rent.
Optional: taxes, insurance, repairs, management, utilities you pay. Not the mortgage. Enter them to see the cap rate beside the GRM.
Gross rent multiplier (annual)
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- Monthly GRM (appraisal forms)
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- Gross rent yield
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- Gross rent, a year
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GRM uses the gross rent and ignores vacancy and expenses: two buildings with the same GRM can have very different cap rates. A lower GRM means more rent for each dollar of price.
The calculation runs in your browser and ParrotNotes does not store your numbers. They sit in the page address so you can bookmark or share the result.
How the gross rent multiplier works
The gross rent multiplier is the price divided by the gross rent: how many years of rent the property costs, before any expense. Gross rent is everything the units would bring in, fully let, with no deduction for vacancy, taxes, insurance or repairs. Turned around, 100 ÷ GRM is the gross rent yield: a GRM of 10 is a 10% gross yield.
Worked example: a fourplex priced at $600,000 with $5,000 of rent a month. A year's rent is $60,000, so the annual GRM is 10 and the monthly GRM is $600,000 ÷ $5,000 = 120. If similar fourplexes nearby sold at a GRM of 9, the same rent supports $540,000; to justify $600,000 at a GRM of 12 the building needs $50,000 a year, $4,166.67 a month.
Annual GRM or monthly GRM
Most investors, listings and online calculators use the annual rent. Appraisers of one- to four-unit homes use the monthly rent: Freddie Mac Form 72 (Fannie Mae Form 1025) shows a gross monthly rent and a gross rent multiplier for every comparable sale, and the income approach line reads total gross monthly rent × GRM = indicated value. Form 70 (Fannie Mae 1004) does the same with the estimated monthly market rent. The calculator shows both, and the target GRM can be typed on either basis.
GRM and cap rate side by side
GRM is a quick screen: you only need the price and the rent, both of which are in the listing. Its weakness is everything it leaves out. Enter a vacancy and the yearly operating expenses (not the mortgage) and the calculator adds net operating income and the cap rate, NOI ÷ price, plus the share of the rent the expenses take. Two properties at a GRM of 10 with expenses of 30% and 50% of the rent are not the same deal; the cap rate shows it.
For a fuller look at one property, with a target cap rate, a loan and cash on cash return, use the cap rate calculator. This page is for the first pass across several listings, and for the multiplier an appraiser or a seller quotes.
What GRM leaves out
GRM does not see vacancy, operating costs, the property's condition, rent below or above market, financing or taxes. Use market rents, not only the rents a seller reports, and compare only with sales of similar properties in the same area on the same basis. It is arithmetic on your numbers, not an appraisal or investment advice.
Sources, each read on 2026-11-01. Results are arithmetic on your own numbers, not an appraisal:
- Freddie Mac Form 72 / Fannie Mae Form 1025, Small Residential Income Property Appraisal Report: sale price, gross monthly rent and GRM per comparable
- Freddie Mac Form 70 / Fannie Mae Form 1004, Uniform Residential Appraisal Report: estimated monthly market rent × GRM
- Fannie Mae Selling Guide B4-1.3-10, Cost and Income Approach to Value: the income approach for two- to four-unit properties
Related: the cap rate calculator for NOI, value at a target cap rate and cash on cash return, the price per square foot calculator to compare listings by size, and the DSCR calculator to see whether the rent covers a loan.
More for real estate agents and investors: Commercial real estate broker: the job and its notes, Property inspection notes by voice, Tips for new real estate agents.
The rents come from the property tour
A GRM is only as good as the rent you put in, and the real rent roll comes out on the tour: what each unit rents for, what the tenant pays, which costs the owner carries. Record the walk-through in ParrotNotes and the summary keeps the rents and expenses you heard, unit by unit.
Get Started FreeRelated tools
- Cap Rate CalculatorWork out a property's cap rate from net operating income and price, the value at a target cap rate, cash on cash return and price per square foot.Open the tool
- Price per Square Foot CalculatorWork out the price per square foot of a home or commercial space, compare listings side by side, and turn a rent per square foot into a monthly figure.Open the tool
- DSCR CalculatorWork out a rental's debt service coverage ratio from rent and PITIA or from NOI, plus the largest loan the rent supports.Open the tool