# Cap Rate vs Gross Rent Multiplier: Two Properties, Same GRM, Half the Return

GRM screens deals in thirty seconds and tells you nothing about expenses. Here are two buildings at an identical 8.93 GRM whose cap rates are 6.04% and 2.70%, plus the formula that converts between the two.

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- **Canonical URL:** https://dothecalculation.com/blog/property/cap-rate-vs-gross-rent-multiplier
- **Category:** Real Estate & Property
- **Author:** Do The Calculation Team
- **Published:** 2026-08-03
- **Reading time:** 12 min read
- **Publisher:** Do The Calculation (https://dothecalculation.com)
- **Methodology:** https://dothecalculation.com/methodology

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## Cap Rate vs Gross Rent Multiplier

Both reduce a rental property to a single number. The gross rent multiplier divides the price by the rent and stops there. The capitalisation rate divides net operating income by the price, which means it first subtracts vacancy and every operating expense.

That difference is the entire subject. GRM is a screening tool you can compute from a listing in ten seconds. Cap rate is an underwriting number you cannot compute without real expense data. Using the first where you needed the second is how people buy properties that lose money.

Tool: [Try the gross rent multiplier calculator](https://dothecalculation.com/calculators/gross-rent-multiplier-calculator) — Compare listings on price against gross rent to shortlist quickly before you request expense figures.

## The two formulas

**GRM and cap rate**

```
GRM = Price ÷ Gross annual rent    ·    Cap rate = Net operating income ÷ Price
```
- GRM is a multiple, so lower is cheaper. A GRM of 8 is better priced than a GRM of 12.
- Cap rate is a percentage, so higher is a better yield. A 7% cap is a higher yield than a 5% cap.
- They move in opposite directions, which is a common source of confusion when reading a comparison table.

> **Check whether the GRM is annual or monthly** — Some markets quote GRM on monthly rent, giving figures around 100 to 130 rather than 8 to 11. The same property is a 8.93 annual GRM and a 107 monthly GRM. Neither is wrong, and comparing one to the other is meaningless. Always confirm which convention a listing uses.

## Two buildings, identical GRM

Both are listed at $450,000 and both collect $4,200 a month, so both have a GRM of 8.93. On the screening number they are the same deal.

**What the expense line actually does**
| Line | Property A, 2012 build | Property B, 1958 build |
| --- | --- | --- |
| Purchase price | $450,000 | $450,000 |
| Gross annual rent | $50,400 | $50,400 |
| GRM | 8.93 | 8.93 |
| Vacancy allowance | 6%, $3,024 | 8%, $4,032 |
| Effective gross income | $47,376 | $46,368 |
| Property taxes | $6,200 | $9,800 |
| Insurance | $2,400 | $4,100 |
| Management at 8% of EGI | $3,790 | $3,709 |
| Repairs and maintenance | $4,000 | $9,500 |
| Utilities paid by owner | $1,800 | $3,600 |
| Capital reserves | $2,000 | $3,500 |
| Total operating expenses | $20,190 | $34,209 |
| Net operating income | $27,186 | $12,159 |
| Cap rate | 6.04% | 2.70% |

Same price, same rent, same GRM, and Property A produces $15,027 more a year. On a 30-year mortgage at 7% covering 75% of the price, the annual debt service is about $26,945. Property A almost covers it. Property B is $14,786 a year short before the owner has taken a cent.

> **The number GRM cannot see** — Property A runs a 42.6% operating expense ratio. Property B runs 73.8%. That single figure is the whole difference, and it is invisible on a listing page. Two thirds of Property B’s rent never reaches the owner.

Tool: [Try the cap rate calculator](https://dothecalculation.com/calculators/cap-rate-market-calculator) — Enter income and each expense line to get net operating income and the resulting cap rate.

## Converting between them

The two are linked by exactly two things: the vacancy rate and the operating expense ratio. If you know those, you can move between GRM and cap rate directly.

**GRM to cap rate**

```
Cap rate = (1 − vacancy) × (1 − expense ratio) ÷ GRM
```
- Property A: 0.94 × 0.574 ÷ 8.93 = 6.04%
- Property B: 0.92 × 0.262 ÷ 8.93 = 2.70%
- Rearranged: GRM = (1 − vacancy) × (1 − expense ratio) ÷ Cap rate

This is genuinely useful for screening. Assume a plausible expense ratio for the property type, convert the listing GRM into an implied cap rate, and reject anything that cannot clear your hurdle even under optimistic assumptions.

**Implied cap rate at a 6% vacancy allowance**
| GRM | At 35% expenses | At 45% expenses | At 60% expenses |
| --- | --- | --- | --- |
| 7 | 8.73% | 7.39% | 5.37% |
| 9 | 6.79% | 5.75% | 4.18% |
| 11 | 5.56% | 4.70% | 3.42% |
| 13 | 4.70% | 3.98% | 2.89% |
| 15 | 4.07% | 3.45% | 2.51% |

Read the top-right corner. A GRM of 7 looks cheap and still only yields 5.37% if expenses run at 60%. Read the bottom-left. A GRM of 15 looks expensive and beats it if the building is genuinely low-cost to run.

## What a plausible expense ratio looks like

**Typical operating expense ratios by property type**
| Property type | Typical range | Driver |
| --- | --- | --- |
| Single family, tenant pays utilities | 30% to 40% | Few shared systems |
| Small multifamily, owner pays some utilities | 40% to 50% | Common areas and heating |
| Older multifamily with deferred maintenance | 55% to 70% | Repairs and higher insurance |
| Self-managed, no reserves booked | Looks like 25%, is not | Unpaid labour and deferred capital |

> **The two lines sellers leave out** — Property management and capital reserves. A seller who manages their own building shows no management fee, and one who has not replaced a roof in twenty years shows no reserve. Add both back at market rates before you compute a cap rate, or you are underwriting a property that does not exist.

## Which one to use, and when

**Matching the tool to the stage**
| Stage | Use | Why |
| --- | --- | --- |
| Scanning fifty listings | GRM | Computable from public data alone |
| Shortlisting five | GRM plus an assumed expense ratio | Filters out the obviously unworkable |
| Making an offer | Cap rate on verified expenses | The only basis for a price |
| Comparing across markets | Cap rate | GRM ignores wildly different tax regimes |
| Comparing near-identical units in one building | GRM is adequate | Expenses are genuinely similar |
| Valuing from an income stream | Cap rate | Price = NOI ÷ market cap rate |

That last row is where cap rate does work GRM cannot do at all. If the market cap rate for the property class is 6%, then raising net operating income by $6,000 a year raises the property value by $100,000. Nothing about GRM expresses that relationship, which is why every commercial valuation runs on cap rate.

Tool: [Try the rental property ROI calculator](https://dothecalculation.com/calculators/rental-property-roi-calculator) — Go past both metrics to cash-on-cash return, which includes financing that neither cap rate nor GRM sees.

## What neither metric tells you

- Neither accounts for financing. Cap rate is deliberately debt-free so that properties can be compared regardless of how they are funded. Your actual return depends on the loan, and that is cash-on-cash return, not cap rate.
- Neither accounts for appreciation. A 4% cap rate in a market growing at 6% a year can outperform an 8% cap in a market that is flat, and no income metric captures that.
- Both are a single year. A property with rents 20% below market has a poor cap rate today and a repricing opportunity, which is exactly the kind of deal a cap rate screen rejects.
- Neither handles capital expenditure honestly. Reserves are an estimate, and a roof, a boiler, or a re-tenanting cost lands in one year rather than spread evenly.
- Both depend entirely on the expense figures being real. A seller-supplied operating statement is a marketing document until you have verified the tax bill, the insurance quote, and twelve months of utility invoices.
- Neither says anything about tax. Depreciation, interest deductibility, and your own marginal rate change the after-tax return substantially and vary by owner.
- Cap rate compresses and expands with interest rates. A 6% cap bought when borrowing costs 4% is a different proposition from the same 6% cap when borrowing costs 7.5%.

**Is a higher GRM better or worse?**

Worse, all else equal. GRM is a price multiple, so a higher number means you are paying more for each dollar of rent. This is the opposite direction from cap rate, where higher is better, and mixing the two up is the most common error with these metrics.

**What is a good cap rate?**

It is market and risk specific, not universal. In a stable urban market, 4% to 6% is common for residential; secondary markets and older stock trade higher because the risk is higher. The useful comparison is against other properties in the same market, not against a number from an article.

**Should mortgage payments be in the cap rate calculation?**

No. Net operating income is calculated before debt service by definition. Including the mortgage would make the cap rate depend on your financing rather than on the property, which defeats the purpose of having a comparable metric.

**Why do two similar buildings have very different cap rates?**

Almost always the expense side: property taxes, insurance in a high-risk area, owner-paid utilities, or deferred maintenance catching up. Occasionally it is the income side, where one building has below-market rents on long leases. Check the expense ratio first.

**Can I use GRM to value a property?**

Only within a narrow set of near-identical properties in one market, where the expense structures are genuinely similar. Across property ages, types, or tax jurisdictions, GRM valuation compares things that only look alike, which is exactly what the two-building example above demonstrates.

**How do I estimate expenses when the seller will not provide them?**

Build them from primary sources. Property tax records are public. Get your own insurance quote. Use local market rates for management, typically 8% to 10% of collected rent. Budget maintenance and reserves from the building age and system condition rather than from what the seller spent.

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_Source: [Do The Calculation](https://dothecalculation.com/blog/property/cap-rate-vs-gross-rent-multiplier). Quote freely with attribution and a link to this page._