- Official section
- National XI.F: Gross Rent and Gross Income Multipliers
- Broker weight
- A named skill within 7% of the national portion
- Expected scored items
- The current PSI broker outline assigns about 7 of 100 scored national items to Real Estate Math
Income-property math guide
Gross rent multiplier with matching rent periods
GRM is quick because it asks only how sale price relates to gross rent. That speed is also its weakness. Before using the formula, label the rent as monthly or annual and confirm that the subject and comparable use the same kind of gross rent. One mismatched label can move the answer by a factor of 12.
Last updated: August 1, 2026
What calculation do you need to make?
Short answer: GRM equals comparable sale price divided by comparable gross rent. Indicated subject value equals subject gross rent times the selected GRM. Implied rent equals value divided by GRM. Monthly price divided by monthly rent produces a monthly GRM; price divided by annual rent produces an annual GRM. Monthly GRM equals annual GRM times 12 when both use the same underlying rent. GRM is a multiplier, not a percentage. It uses gross rent rather than NOI and does not explicitly account for vacancy or operating expenses, so comparable income definitions and expense relationships must be reasonably consistent.
The PSI outline expressly names gross rent and gross income multipliers. Exam questions often provide one comparable and a clean rent figure. Actual valuation requires a defined interest and effective date, verified sale and rent data, comparable market evidence, consistent property rights, and analysis of location, condition, tenancy, concessions, vacancy, expenses, and other differences. An analyst also checks whether utilities, furniture, parking, or services are bundled into rent and whether unusual financing, related parties, personal property, or sale concessions affected the comparable price. A recorded price and an advertised rent are not automatically reliable inputs. Several relevant sales can expose a defensible range and reveal an outlier that one apparently simple comparable would conceal during final reconciliation. GRM is a simplified screening or valuation tool, not a complete appraisal, investment recommendation, or universal market rule. Sources were checked through August 1, 2026.
How do you solve GRM questions?
- Box the unknown: multiplier, subject value, missing rent, monthly GRM, or annual GRM.
- Label every rent as monthly or annual and identify whether it is rent only or a broader gross-income figure.
- For a comparable, divide verified sale price by that comparable's consistent gross rent.
- For the subject, multiply consistent subject rent by the selected market GRM.
- To find missing rent, divide value by the GRM and preserve the multiplier's time period.
- When several comparables are supplied, calculate each GRM separately, identify outliers, and follow the selection instruction.
- Keep GRM as a multiplier and never substitute NOI, cap rate, vacancy loss, or expense ratio into the formula.
- Reverse-check the arithmetic and confirm that the rent period, income line, and output unit all match.
- Unknown
- Monthly GRM
- Formula
- Price / monthly gross rent
- Exam safeguard
- Label as monthly
- Unknown
- Annual GRM
- Formula
- Price / annual gross rent
- Exam safeguard
- Label as annual
- Unknown
- GRM value
- Formula
- Subject gross rent x selected GRM
- Exam safeguard
- Match rent period
- Unknown
- Implied gross rent
- Formula
- Value / selected GRM
- Exam safeguard
- State monthly or annual
- Unknown
- Annual rent
- Formula
- Monthly rent x 12
- Exam safeguard
- Do not multiply GRM too
- Unknown
- Monthly rent
- Formula
- Annual rent / 12
- Exam safeguard
- Use same income definition
- Unknown
- Annual GRM from monthly
- Formula
- Monthly GRM / 12
- Exam safeguard
- Same property and rent
- Unknown
- Monthly GRM from annual
- Formula
- Annual GRM x 12
- Exam safeguard
- Same property and rent
- Unknown
- Comparable range
- Formula
- Lowest through highest extracted GRM
- Exam safeguard
- Inspect outliers
- Unknown
- Cap-rate input
- Formula
- Annual NOI, not gross rent
- Exam safeguard
- Use a different formula
Can you follow the calculation from facts to answer?
Extract and apply a monthly GRM
Scenario: A comparable sold for $360,000 and rents for $3,000 per month. The subject's consistent monthly rent is $3,250.
- Comparable monthly GRM is $360,000 / $3,000 = 120.
- Subject value indication is $3,250 x 120 = $390,000.
- Both rents use the same monthly period.
Answer: The indicated subject value is $390,000.
Convert monthly GRM to annual GRM
Scenario: A property sells for $480,000 and rents for $4,000 per month. Find both monthly and annual GRM.
- Monthly GRM is $480,000 / $4,000 = 120.
- Annual rent is $4,000 x 12 = $48,000.
- Annual GRM is $480,000 / $48,000 = 10, which also equals 120 / 12.
Answer: Monthly GRM is 120 and annual GRM is 10.
Recover missing monthly rent
Scenario: A property has an indicated value of $420,000 under a selected monthly GRM of 140. What monthly gross rent is implied?
- Use rent equals value divided by GRM.
- $420,000 / 140 = $3,000.
- Because the multiplier is monthly, the answer is monthly rent.
Answer: The implied monthly gross rent is $3,000.
Reconcile a three-sale GRM range
Scenario: Three comparable monthly GRMs are 118, 121, and 145. The problem says the third sale has an unusual below-market lease and instructs you to rely on the two similar sales. Subject monthly rent is $3,500.
- The relevant GRMs are 118 and 121, while 145 is identified as less comparable.
- If the question directs an equal average of the two, selected GRM is (118 + 121) / 2 = 119.5.
- $3,500 x 119.5 = $418,250.
Answer: The instructed GRM indication is $418,250.
Catch a factor-of-12 mistake
Scenario: A student applies an annual GRM of 10 directly to monthly rent of $4,000 and reports $40,000 value.
- The annual multiplier requires annual rent.
- Annual rent is $4,000 x 12 = $48,000.
- $48,000 x 10 = $480,000, which matches a monthly GRM of 120.
Answer: The correct indicated value is $480,000, not $40,000.
Recognize the expense limitation
Scenario: The subject and comparable each collect $60,000 in annual gross rent, but the subject pays substantially more for owner-provided utilities and repairs.
- GRM sees the same gross rent but does not explicitly subtract either property's expenses.
- The comparable multiplier can overstate subject value when the subject's expense burden is materially higher.
- An NOI-based analysis provides a better cross-check when supported income and expenses are available.
Answer: Do not treat the unadjusted comparable GRM as conclusive.
Which math errors cost the most points?
- Trap
- Treat GRM as a percentage.
- Correction
- Use a GRM of 120 as the multiplier 120, not 120% or 1.20.
- Trap
- Divide rent by sale price to extract GRM.
- Correction
- GRM equals sale price divided by consistent gross rent.
- Trap
- Use NOI in a GRM formula.
- Correction
- GRM uses gross rent; NOI belongs in capitalization-rate math.
- Trap
- Mix monthly rent with an annual GRM.
- Correction
- Convert the rent or multiplier so both use the same time period.
- Trap
- Call monthly and annual GRM numerically identical.
- Correction
- For the same property, monthly GRM is 12 times annual GRM.
- Trap
- Include laundry income in a rent-only GRM without instruction.
- Correction
- Use nonrent income only when the problem defines a broader GIM measure.
- Trap
- Subtract operating expenses before calculating GRM.
- Correction
- That creates a net-income measure rather than the stated gross-rent multiplier.
- Trap
- Assume equal gross rents mean equal values.
- Correction
- Location, condition, expenses, vacancy, lease terms, and other market factors can support different multipliers.
- Trap
- Average every comparable even when the problem identifies an outlier.
- Correction
- Follow the reconciliation instruction and analyze relevance before applying equal weight.
- Trap
- Assume a higher GRM always means a better investment.
- Correction
- GRM is a price-to-rent relationship, not a complete return, risk, expense, or investment analysis.
- Trap
- Use subject value to derive the market GRM before value is known.
- Correction
- Extract GRM from verified comparable sales, then apply it to the subject.
- Trap
- Call a single GRM result a complete appraisal.
- Correction
- It is a simplified indication that requires proper data, scope, analysis, and reconciliation in actual valuation.
Can you solve these original problems?
These questions are original study items aligned to the published outline. They are not copied, recalled, or predicted PSI questions.
1. A comparable sold for $480,000 and rents for $4,000 per month. What is its monthly GRM?
- 120
- 10
- 0.0083
- 1,920
Show answer and explanation
Answer: 120
$480,000 / $4,000 = 120.
2. A subject rents for $3,200 per month and the selected monthly GRM is 125. What is indicated value?
- $400,000
- $384,000
- $25,600
- $128,000
Show answer and explanation
Answer: $400,000
$3,200 x 125 = $400,000.
3. A $360,000 value is supported by a monthly GRM of 120. What monthly rent is implied?
- $3,000
- $2,500
- $30,000
- $43,200
Show answer and explanation
Answer: $3,000
$360,000 / 120 = $3,000 per month.
4. A property's monthly GRM is 144. What is the equivalent annual GRM using the same rent?
- 12
- 1,728
- 144
- 0.0833
Show answer and explanation
Answer: 12
Annual GRM equals monthly GRM divided by 12, so 144 / 12 = 12.
5. Which income belongs in a standard GRM formula?
- Consistently defined gross rent
- Net operating income
- Cash flow after debt service
- Taxable income after depreciation
Show answer and explanation
Answer: Consistently defined gross rent
GRM uses gross rent and does not explicitly deduct operating expenses.
Which numbers and formulas are easy to confuse?
- Terms
- GRM vs. capitalization rate
- Difference
- GRM is a price-to-gross-rent multiplier. Cap rate is an NOI-to-value percentage.
- Question cue
- Gross multiplier versus net-income rate.
- Terms
- Gross rent vs. NOI
- Difference
- Gross rent is scheduled or defined rental income before explicit operating deductions. NOI remains after vacancy treatment and operating expenses under the stated setup.
- Question cue
- Top-line rent versus property income after expenses.
- Terms
- Monthly GRM vs. annual GRM
- Difference
- Monthly GRM divides by one month's rent. Annual GRM divides by 12 months of rent and is one-twelfth as large for the same property.
- Question cue
- One-month denominator versus one-year denominator.
- Terms
- Multiplier vs. percentage
- Difference
- A multiplier such as 120 is used as 120. A percentage such as 8% becomes 0.08 in arithmetic.
- Question cue
- Whole factor versus rate per hundred.
- Terms
- GRM vs. GIM
- Difference
- GRM focuses on rent. GIM can use a broader gross-income measure including stated nonrent income.
- Question cue
- Rent only versus defined gross income.
- Terms
- Contract rent vs. market rent
- Difference
- Contract rent is set by the lease. Market rent is the rent market participants would expect under current market conditions.
- Question cue
- Lease fact versus market estimate.
- Terms
- Potential rent vs. effective income
- Difference
- Potential rent assumes the selected full-rent basis. Effective income reflects vacancy and collection loss and may include other income.
- Question cue
- Full potential versus expected collection.
- Terms
- Comparable GRM vs. subject GRM
- Difference
- A comparable GRM is extracted from known sale and rent. A subject indication applies a selected market multiplier to subject rent.
- Question cue
- Derive from sale versus apply to subject.
- Terms
- GRM range vs. simple average
- Difference
- A range displays market evidence. A simple average assigns equal weight even when one sale is less comparable or an outlier.
- Question cue
- Evidence spread versus mechanical midpoint.
- Terms
- Value indication vs. appraisal conclusion
- Difference
- A GRM result is one simplified indication. A complete appraisal follows its scope, data, methods, reconciliation, standards, and licensing requirements.
- Question cue
- Formula output versus developed opinion.
What does the outline expect you to calculate?
- Topic
- GRM purpose
- What to know
- Income property, rental property, market comparison, sale price, gross rent, multiplier, value indication, screening, small residential income property, investor, and simplified method
- Best exam move
- Use GRM when the problem supplies comparable price and consistent gross-rent evidence.
- Topic
- GRM extraction formula
- What to know
- Comparable sale price, comparable rent, division, monthly GRM, annual GRM, multiplier, quotient, market extraction, sale verification, and rent verification
- Best exam move
- Divide comparable price by that same comparable's gross rent for the stated period.
- Topic
- GRM value formula
- What to know
- Subject rent, selected multiplier, indicated value, multiplication, market rent, contract rent, gross rent, estimate, and reconciliation
- Best exam move
- Multiply subject rent by a GRM derived with the same period and rent definition.
- Topic
- Missing-rent formula
- What to know
- Indicated value, selected GRM, implied rent, division, monthly rent, annual rent, affordability, market check, and reverse formula
- Best exam move
- Divide value by GRM and label the result with the multiplier's monthly or annual period.
- Topic
- Monthly GRM
- What to know
- Monthly gross rent, one month, price divided by monthly amount, large multiplier, 100, 120, 150, rent roll, and subject month
- Best exam move
- Use monthly rent for both comparable extraction and subject application.
- Topic
- Annual GRM
- What to know
- Annual gross rent, 12 months, annualized rent, price divided by annual amount, smaller multiplier, 8, 10, 12.5, calendar year, and lease year
- Best exam move
- Annualize all rent consistently before extracting or applying an annual multiplier.
- Topic
- Monthly-to-annual conversion
- What to know
- Monthly rent times 12, annual rent divided by 12, monthly GRM divided by 12, annual GRM times 12, factor of 12, same property, and unit conversion
- Best exam move
- Convert the rent and multiplier deliberately instead of mixing periods inside one equation.
- Topic
- Gross rent definition
- What to know
- Scheduled rent, contract rent, market rent, potential rent, actual rent, concessions, vacancy, collection loss, furnished rent, utilities, and lease term
- Best exam move
- Use the rent definition stated and demand the same definition across subject and comparables.
- Topic
- Gross income multiplier
- What to know
- GIM, gross income, rent, parking, laundry, storage, vending, reimbursement, other income, price, multiplier, and consistent income line
- Best exam move
- Include nonrent income only when the metric and comparable data expressly use broader gross income.
- Topic
- GRM versus NOI
- What to know
- Gross rent, vacancy, collection loss, effective gross income, operating expense, net operating income, debt service, depreciation, and income waterfall
- Best exam move
- Stop at gross rent for GRM and reserve NOI for direct-capitalization formulas.
- Topic
- Expense limitation
- What to know
- Property tax, insurance, utilities, maintenance, management, repairs, owner-paid service, replacement reserve, expense ratio, high expense, low expense, and hidden burden
- Best exam move
- Recognize that GRM does not explicitly adjust for an expense burden unlike the comparables.
- Topic
- Vacancy limitation
- What to know
- Physical vacancy, economic vacancy, collection loss, concession, turnover, lease-up, occupancy, gross rent, effective income, market vacancy, and uncollected amount
- Best exam move
- Do not claim that equal gross rent means equal collected income when vacancy differs.
- Topic
- Comparable selection
- What to know
- Location, property type, unit mix, condition, age, quality, rights conveyed, financing terms, sale conditions, market date, rent level, expenses, and tenancy
- Best exam move
- Select sales whose rent and operating relationships make their multipliers relevant to the subject.
- Topic
- Multiple-comparable range
- What to know
- Low GRM, high GRM, mean, median, range, outlier, weighting, reconciliation, subject position, superior comparable, inferior comparable, and market support
- Best exam move
- Calculate each comparable separately and support the selected multiplier rather than blindly averaging an outlier.
- Topic
- Higher and lower GRM
- What to know
- Higher multiplier, lower multiplier, fixed rent, higher value, lower value, market preference, growth, risk, condition, expense relationship, and sensitivity
- Best exam move
- With subject rent fixed, a larger GRM produces a larger indicated value.
- Topic
- GRM versus cap rate
- What to know
- Multiplier, percentage, gross rent, NOI, value, multiplication, division, expenses, market extraction, return measure, and inverse confusion
- Best exam move
- Use GRM with gross rent and cap rate with NOI; never convert one into the other without sufficient income and expense data.
- Topic
- Appraisal boundary
- What to know
- Broker price opinion, CMA, appraisal, licensed appraiser, USPAP, intended use, scope of work, data verification, reconciliation, value opinion, and disclaimer
- Best exam move
- Solve the exam calculation without representing a shortcut as a complete licensed appraisal.
- Topic
- Precision and checking
- What to know
- Decimal multiplier, whole multiplier, rent period, dollar value, exact quotient, rounding, answer choices, reverse check, factor-of-12 error, and reasonableness
- Best exam move
- Reverse the formula and confirm the answer's units before selecting a choice.
How should you drill this calculation?
- Session
- Session 1
- Focus
- Master the three formulas
- Proof you are ready
- Solve ten missing-GRM, ten missing-value, and ten missing-rent problems with reverse checks.
- Session
- Session 2
- Focus
- Control time periods
- Proof you are ready
- Convert 30 monthly and annual rents or GRMs without a factor-of-12 error.
- Session
- Session 3
- Focus
- Classify income lines
- Proof you are ready
- Sort 40 rent, other-income, vacancy, EGI, expense, NOI, debt-service, and cash-flow facts into GRM, GIM, cap rate, or neither.
- Session
- Session 4
- Focus
- Extract comparable GRMs
- Proof you are ready
- Calculate 20 sale multipliers and identify period mismatches, inconsistent rent definitions, and outliers.
- Session
- Session 5
- Focus
- Apply and reconcile
- Proof you are ready
- Use GRM ranges to produce 15 subject indications and explain the selected multiplier in one sentence each.
- Session
- Session 6
- Focus
- Complete a mixed GRM set
- Proof you are ready
- Score at least 90% and justify each answer by formula direction, rent definition, time period, multiplier, comparable support, and limitation.
Do not count recognition as mastery. Close the notes and explain the rule, apply it to a new fact pattern, and identify why each distractor fails.
Build speed without skipping the setup
From concept to decision
Drill this topic, then review the explanation
Pass Illinois gives you original national and Illinois questions, topic-by-topic study, clear explanations, timed practice, flashcards, progress tracking, and Math Coach. Start free, find the weak distinction, and focus the next session there.
Questions students ask about Gross Rent Multiplier Formula and Examples
What is the gross rent multiplier formula?
GRM equals comparable sale price divided by comparable gross rent for the same period. If a property sells for $360,000 and its gross monthly rent is $3,000, the monthly GRM is 120.
How do you calculate value with GRM?
Multiply the subject's consistent gross rent by a market-supported GRM. If the subject's monthly rent is $3,250 and the selected monthly GRM is 120, the indicated value is $390,000.
How do you find missing rent with a GRM?
Divide value or sale price by the consistent GRM. If indicated value is $420,000 and the monthly GRM is 140, implied monthly gross rent is $3,000.
Is GRM based on monthly or annual rent?
It can use either, but the period must stay consistent. A monthly GRM is price divided by monthly gross rent. An annual GRM is price divided by annual gross rent. State the period because the numerical multipliers differ by a factor of 12.
Is a GRM a percentage?
No. GRM is a multiplier. A GRM of 120 is used as 120 in value equals rent times GRM. It is not 120%, 1.20, or a capitalization rate.
Does GRM use net operating income?
No. GRM uses gross rent and does not explicitly subtract vacancy, collection loss, or operating expenses. Direct capitalization uses NOI. Mixing NOI into a GRM formula changes the metric and produces a meaningless answer.
What is the difference between GRM and GIM?
Gross rent multiplier focuses on rent. Gross income multiplier can use a broader gross-income measure that includes qualifying nonrent income. Follow the definition used by the comparable data and the exam question rather than treating the labels as automatic synonyms.
Does a higher GRM mean a higher property value?
For the same subject rent, yes. Value equals rent times GRM, so a higher selected multiplier creates a higher indication. That does not mean a higher GRM is always better because the market-supported multiplier reflects property and income characteristics.
Can one comparable sale establish the right GRM?
One sale can supply an exam multiplier, but actual valuation requires relevant market evidence and analysis. A selected GRM should reflect comparability in location, property type, condition, rent definition, lease terms, vacancy, expense relationships, rights conveyed, and sale conditions.
Are these official Illinois broker exam questions?
No. They are original calculations aligned to the PSI broker outline effective June 24, 2026. Current Illinois appraisal oversight and current federal, appraisal-standards, banking, and agency materials were checked through August 1, 2026.
Primary sources
- PSI Illinois Candidate Information Booklet dated June 24, 2026
- Illinois Department of Financial and Professional Regulation, current appraisal oversight
- The Appraisal Foundation, current Uniform Standards of Professional Appraisal Practice
- U.S. Department of Justice, Uniform Appraisal Standards for Federal Land Acquisitions
- Office of the Comptroller of the Currency, current Commercial Real Estate Lending handbook
- Fannie Mae Selling Guide B4-1.3-09, current comparable-sale adjustment guidance
The current official outline controls the tested scope. Statutes, regulations, and official agency materials control when a general study rule and a jurisdiction-specific rule differ.
Editorial status
Checked against primary sources
The Pass Illinois editorial team last checked this guide on August 1, 2026. Every practice question is an original study item, and the source links above let you verify the rules that support the lesson.