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June 17, 2026
What Is Cap Rate in Real Estate? Formula, Examples, and What Makes a Good Number
Table of Contents
- Quick answer
- Introduction
- The Cap Rate Formula
- The Reverse Formula: Using Cap Rate to Estimate Property Value
- What Goes Into NOI (And What Doesn't)
- What Is a Good Cap Rate?
- Cap Rate vs Cash-on-Cash Return: The Difference That Matters
- What Cap Rate Cannot Tell You
- How Cap Rate Fits Into a Complete Property Analysis
- Frequently Asked Questions
Quick answer
Cap rate, short for capitalization rate, is a property's annual net operating income (NOI) divided by its current market value, expressed as a percentage. A property generating $50,000 in NOI worth $800,000 has a cap rate of 6.25%. Higher cap rates generally indicate higher returns with more risk. Lower cap rates indicate lower returns with less risk.
Introduction
If you spend any time around real estate investing, cap rate is one of the first terms you will hear. Brokers quote it. Sellers advertise it. Investors use it to compare properties across cities and asset classes in seconds.
But cap rate is also one of the most misunderstood numbers in real estate. People confuse it with cash-on-cash return, use it without calculating NOI correctly, and treat a single number as a complete investment verdict when it is really just a starting point.
This guide explains what cap rate actually is, how to calculate it correctly, what counts as a good cap rate in different US markets, what the number cannot tell you, and how it fits into a complete picture of an investment property's performance.
The Cap Rate Formula
Cap Rate = (Net Operating Income / Property Value) × 100
Where:
Net Operating Income (NOI) is your annual rental income minus all operating expenses. Operating expenses include property taxes, insurance, property management fees, maintenance and repairs, vacancy allowance, and any other recurring costs of running the property. NOI does not include mortgage payments. Financing costs are excluded by design, because cap rate is meant to measure the return on the asset itself, independent of how it is financed.
Property Value is either the current market value or the purchase price, depending on what you are measuring.
Worked example
A duplex in Chicago generates $3,200 per month in total rent across both units.
Annual rental income: $3,200 × 12 = $38,400
Annual operating expenses:
Expense Annual Cost Property taxes $5,200 Insurance $1,800 Property management (10%) $3,840 Maintenance $2,400 Vacancy allowance (5%) $1,920 Total expenses $15,160 NOI: $38,400 minus $15,160 = $23,240
If the property is worth $350,000:
Cap Rate = ($23,240 / $350,000) × 100 = 6.64%
A 6.64% cap rate on a Chicago duplex sits solidly in the normal range for that market.
The Reverse Formula: Using Cap Rate to Estimate Property Value
One of the most useful applications of cap rate is running the formula in reverse to estimate what a property should be worth based on what similar properties trade at in the local market.
Property Value = NOI / Cap Rate
If comparable properties in your target neighborhood trade at a 6.5% cap rate, and the property you are evaluating has an NOI of $42,000:
Property Value = $42,000 / 0.065 = $646,154
If the seller is asking $750,000, the cap rate implied by that price is:
$42,000 / $750,000 = 5.6%
Whether 5.6% is acceptable depends on whether you believe the local market supports that cap rate, and whether the NOI has room to grow. This is where cap rate becomes a negotiating and underwriting tool, not just a reporting metric.
What Goes Into NOI (And What Doesn't)
Getting cap rate right depends almost entirely on calculating NOI correctly. This is where most mistakes happen.
Include in NOI:
- All rental income across all units
- Pet fees, parking income, laundry income, or other recurring property income
- Minus vacancy allowance (typically 5% to 10% of gross rent)
- Minus property taxes
- Minus landlord insurance
- Minus property management fees
- Minus maintenance and repairs
- Minus any HOA or condo association fees
Do not include in NOI:
- Mortgage principal and interest payments
- Depreciation
- Capital expenditures (roof replacement, HVAC, major renovations)
- Income taxes
Mortgage payments are excluded because cap rate is designed to measure the return of the asset regardless of how it is financed. Two investors could buy the same property at the same price with very different mortgage terms and arrive at the same cap rate, because financing is not part of the calculation.
Capital expenditures are excluded from NOI but matter enormously to your actual return. A property with a 7% cap rate and a roof that needs replacement in two years is a different proposition from one with a 7% cap rate and a new roof. Cap rate captures neither of these distinctions, which is why it is a starting point and not a complete analysis.
What Is a Good Cap Rate?
There is no universal answer. Cap rates vary by market, property type, property class, and the broader interest rate environment. Commercial real estate investors tend to look for cap rates in the 4% to 10% range, but what is appropriate within that range depends on several factors.
How interest rates affect cap rates:
Interest rates and cap rates move in relation to each other. When rates are low, investors accept lower cap rates because their borrowing costs are low and competition for assets is high. When rates rise, cap rates tend to expand because higher borrowing costs reduce the price investors are willing to pay for a given income stream.
The practical implication: what counts as a good cap rate changes with the interest rate environment. A 4 to 5% cap rate made sense when mortgage rates were near 3%. The same property at the same cap rate looks very different when borrowing costs are at 7%. Always compare cap rates to the current rate environment rather than historical averages.
The risk spectrum:
A 5% cap rate means you're paying 20 times the property's annual NOI. Low caps are common in trophy multifamily, net-lease deals with investment-grade tenants, and core industrial in gateway markets. You're paying a premium because the risk is low, the tenant is strong, the asset is liquid, and you expect rents to grow over time. A 9% or 10% cap rate typically signals a value-add opportunity, a secondary market, or some form of elevated risk that the market is pricing in.
Cap Rate vs Cash-on-Cash Return: The Difference That Matters
Cap rate and cash-on-cash return are related but answer different questions, and confusing them is one of the most common mistakes new investors make.
Cap rate measures the return on the asset itself, before financing. It ignores your mortgage entirely.
Cash-on-cash return measures the return on your actual cash investment, after financing. It reflects how much cash you receive relative to how much cash you put in.
Using the Chicago duplex from the earlier example:
- NOI: $23,240
- Property value: $350,000
- Cap rate: 6.64%
Now add financing: you put 25% down ($87,500) and take an $262,500 mortgage at 7% interest over 30 years. Annual mortgage payment: approximately $20,964.
Cash flow after debt service: $23,240 minus $20,964 = $2,276
Cash-on-cash return: $2,276 / $87,500 = 2.6%
The cap rate is 6.64%. The cash-on-cash return is 2.6%. Both numbers are real and meaningful. The cap rate describes the asset. The cash-on-cash return describes your experience as a leveraged investor.
In a higher interest rate environment, the gap between these two numbers widens. A property with a 6% cap rate and a 7% mortgage rate is a neutral-to-negative cashflow situation for a leveraged buyer. This is why cap rate compression combined with rising interest rates puts pressure on investment returns: the spread between cap rates and borrowing costs narrows, reducing the benefit of leverage.
What Cap Rate Cannot Tell You
Cap rate is a useful snapshot. It is not a complete investment analysis. Here is what it misses.
Future NOI growth. A property with a 5% cap rate and 8% annual rent growth can outperform a 7% cap rate property with flat rents over a 10-year hold. Cap rate captures neither trajectory.
Capital expenditure needs. Two properties with identical cap rates could have very different maintenance and improvement requirements. The one that needs a new HVAC system, roof, and plumbing in year three has a meaningfully different actual return than the cap rate implies.
Financing and leverage. Cap rate is unlevered. Your actual return depends on how much you borrow, at what rate, and for how long. Two investors buying the same property at the same cap rate can have completely different returns depending on their financing terms.
How the property fits your overall financial position. A single-property cap rate tells you nothing about how that property interacts with your other assets, your tax situation, your retirement timeline, or your net worth trajectory. These are the questions that actually matter for long-term wealth building.
How Cap Rate Fits Into a Complete Property Analysis
Cap rate is best used as a first filter, not a final verdict. Here is how it fits into a complete investment property evaluation.
Start with cap rate to quickly compare a property against others in the same market and asset class. If the cap rate is significantly above or below comparable properties, find out why before proceeding. A high cap rate can mean an opportunity or a problem. A low cap rate can mean a premium asset or an overpriced one.
Then move to cash-on-cash return to understand the actual cashflow impact after financing. This tells you whether the property will require you to contribute cash each month or generate positive cashflow from day one.
Then model the full projection: how does the property value grow over time, how does your equity build as the mortgage pays down, what does your NOI look like in year 5 and year 10 as rents grow, and how does this property fit into your overall net worth?
Calm Sea's investment property tracker handles all of this in one place. You enter the property's current value, rental income, expense assumptions, and loan details. Calm Sea calculates your cap rate, cashflow, LVR, and equity position, and projects all of them forward year by year. It then rolls the property into your total net worth view alongside your other assets so you can see how your investment property fits into your complete financial picture.
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Frequently Asked Questions
Calm Sea is a personal finance planning tool. Nothing in this article constitutes financial advice. All projections and calculations are illustrative estimates based on publicly available market data. Always conduct your own due diligence and consult a qualified financial adviser or real estate professional before making investment decisions.
