Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Gross rent multiplier at asking price
7.33
Implied value at target GRM
$1,166,400
Actual annual gross rent from roll
$129,600
Asking price above/below implied value
-$216,400
Blended average rent per unit
$1,350
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How to use this
- 1Enter unit type a: count.
- 2Enter unit type a: monthly rent each ($).
- 3Enter unit type b: count.
- 4Enter unit type b: monthly rent each ($).
- 5Enter purchase price ($).
- 6Enter target / market grm.
- 7Read your gross rent multiplier at asking price on the right — it updates as you type.
- 8Hit Share to keep the scenario or send it to someone.
About this calculator
Gross rent multiplier (price ÷ annual gross rent) is a fast screening tool, but most GRM calculators assume one uniform rent across all units, which misprices any property with a mixed unit mix. This tool sums actual rent roll income across different unit types at their real rents, then computes GRM and an implied value at a target multiplier, so you can screen deals off the real rent roll a broker sends you rather than an averaged number that hides upside from below-market units or risk from above-market ones.
Worked example
Using the values the calculator loads with:
Inputs
- Unit type A: count: 4
- Unit type A: monthly rent each: 1200 $
- Unit type B: count: 4
- Unit type B: monthly rent each: 1500 $
- Purchase price: 950000 $
- Target / market GRM: 9
Results
- Gross rent multiplier at asking price: 7.33
- Implied value at target GRM: $1,166,400
- Actual annual gross rent from roll: $129,600
- Asking price above/below implied value: -$216,400
- Blended average rent per unit: $1,350
What each field means
Inputs
- Unit type A: count
- The unit type a: count used in the calculation. Starts at 4 so you have a working example on load.
- Unit type A: monthly rent each ($)
- The unit type a: monthly rent each used in the calculation, measured in $. Starts at 1200 $ so you have a working example on load.
- Unit type B: count
- The unit type b: count used in the calculation. Starts at 4 so you have a working example on load.
- Unit type B: monthly rent each ($)
- The unit type b: monthly rent each used in the calculation, measured in $. Starts at 1500 $ so you have a working example on load.
- Purchase price ($)
- The purchase price used in the calculation, measured in $. Starts at 950000 $ so you have a working example on load.
- Target / market GRM
- The target / market grm used in the calculation. Starts at 9 so you have a working example on load. Accepted range: 1–30.
Results
- Gross rent multiplier at asking price
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Implied value at target GRM
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Actual annual gross rent from roll
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Asking price above/below implied value
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Blended average rent per unit
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why use rent roll GRM instead of a simple average-rent GRM?
A property with six $1,000 units and two $2,000 units has a very different rent roll than eight units averaging $1,250 — even though the average is identical, the composition changes renovation upside and tenant risk profile. Rent roll GRM forces you to actually enter the real unit mix instead of a misleading blended average.
What's a good GRM?
It varies hugely by market — GRM of 6-9 is common in cash-flow-oriented Midwest and Southeast markets, while 12-20+ shows up in coastal high-appreciation markets where investors accept lower current yield for growth. Always compare GRM to recent comparable sales in the same submarket, never to a national number.
What does GRM leave out that cap rate captures?
GRM ignores operating expenses entirely, so two properties with identical rent rolls but very different expense ratios (older building with high maintenance vs. newer with low) will look identical on GRM but very different on cap rate and cash flow. Use GRM to screen quickly, then underwrite NOI and cap rate before making an offer.
Should I use actual or market rents for GRM?
Use actual in-place rents for valuing what you're buying today, and separately calculate a pro forma GRM at market rents to show upside potential. Sellers sometimes market off pro forma rents to make a property look cheaper than it is on today's actual income.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Rent Roll Gross Rent Multiplier Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/rent-roll-grm
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/rent-roll-grm" target="_blank" rel="noopener">Rent Roll Gross Rent Multiplier Calculator — RevenueLab</a> (2026).</p>
Source: [Rent Roll Gross Rent Multiplier Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/rent-roll-grm) (2026).