How to Value a Rental Property With Cap Rate (Income Approach)

Value equals net operating income divided by the market cap rate. If similar rentals in a submarket sell at a 6% cap rate and a property produces $18,270 of NOI, it is worth about $304,500. That is the income approach to valuation, and it is how appraisers, lenders and experienced buyers price income property.

Value = NOI / market cap rate

The formula is trivial. Getting the two inputs right is the work.

Step 1: build a defensible NOI

Use the property’s income and expenses as a typical buyer would operate it, not as the current owner does. That means:

• Rent at market, supported by comparable leases. Not the seller’s projection.
• Vacancy of 5% or the submarket’s actual rate.
• Property taxes after reassessment at the new price.
• Real insurance quotes.
• Management at 8 to 10%, even if you will self-manage, because the next buyer and the appraiser will include it.
• Maintenance and capital reserves at 5 to 10% each.
• HOA, owner-paid utilities and other actual costs.

The cap rate formula guide lists every line. An NOI built this way can be defended to a lender or a seller. One that omits management and reserves cannot.

Step 2: find the market cap rate

Pull recent sales of similar property in the same area: same type, similar age and condition, similar tenant profile. For each, rebuild NOI on the same assumptions you used in step 1 and divide by the sale price. The cluster of results is the market cap rate.

Consistency matters more than precision. If you include management and reserves in your subject’s NOI but not in the comparables’, you will understate the subject’s value by a point of cap rate.

Published cap rates from brokers and listing services are a starting point. Check what expense convention they used. Many are computed on seller pro formas that omit vacancy and management, which makes them run a point or more below what an honest NOI would produce on the same sales.

Step 3: divide

$18,270 / 0.06 = $304,500. Round to the nearest few thousand; the inputs are not precise enough for more.

The calculator does this on the “value at target cap rate” line. Enter the market cap rate as the target, and it shows the value the NOI supports and how far the asking price is from it.

What the result is sensitive to

Cap rate. The same $18,270 of NOI is worth $365,400 at 5%, $304,500 at 6%, $261,000 at 7% and $228,375 at 8%. One point of cap rate moves value by 12 to 20%. This is why disagreements between buyers and sellers are usually about cap rate, not about NOI.

NOI. At a 6% cap rate, every $1,000 of annual NOI is worth $16,667. Every $100 a month of rent, after vacancy and percentage expenses, is worth about $15,600. A $600 insurance saving is worth $10,000. Small operating changes produce large value changes, which is the whole thesis behind value-add investing.

Using cap rate to set an offer

Build NOI on your assumptions. Divide by the market cap rate. That is the property’s value to a typical buyer. Offer at or below it, and you can show the seller the math.

If the asking price implies a cap rate below the market, ask what justifies it. Sometimes there is an answer: a below-market lease resetting soon, a lot with development potential, a location that trades at a premium. Often there is not, and the price is a seller’s hope.

The calculator’s “rent needed at this price” figure turns the same math around: it shows what rent the property would need to justify the asking price at the market cap rate. If that rent is above market, the price is too.

Using cap rate to price a sale

Sellers work the same formula forward. Raise NOI, and value rises by NOI divided by the cap rate. In the two years before a sale:

• Bring rents to market at each renewal. $100 a month across a fourplex is $400 a month, about $3,700 of NOI after vacancy and percentage expenses, and about $62,000 of value at 6%.
• Shop insurance, appeal the tax assessment, bill back utilities where leases allow.
• Add income lines: pet rent, storage, parking, laundry.
• Document everything. A buyer who can verify the NOI will pay a lower cap rate for it than one who cannot.

Deferred maintenance works the other way. Buyers deduct it from value dollar for dollar and often add a cap rate premium for the uncertainty.

Cap rate compression and expansion

When market cap rates fall, every property in the market gains value without earning another dollar. From 6% to 5%, the $18,270 property gains $60,900. That is compression, and it drove much of the price appreciation of the 2010s as interest rates fell.

When cap rates rise, values fall the same way. From 6% to 7%, the same property loses $43,500. That is expansion, and it is what happened to income property values when rates rose in 2022 and 2023, offset in many markets by rent growth. The cap rate and interest rates guide covers the link.

Where the income approach stops

Single-family rentals in owner-occupant neighborhoods mostly sell to people who will live in them, and those buyers do not care about NOI. Comparable sales set the price, and the cap rate is whatever falls out. The income approach still tells you what the property is worth to you as a landlord, which may be less than what an owner-occupant will pay. When it is, sell to the owner-occupant.

For two to four units, the two approaches share the field. For five or more, income rules.

The cap rate pages show what a given NOI is worth at every rate from 3% to 12%, and the good cap rate guide covers where the market rate is likely to sit for a given property type.