Calculator guide
Cap Rate Calculator
Cap rate measures how a property performs on its own — before any loan is involved. That makes it a useful way to compare properties regardless of how they're financed.
What this metric tells you
Cap rate measures how a property performs on its own — before any loan is involved. That makes it a useful way to compare properties regardless of how they're financed.
DealPrism uses cap rate as an estimated unlevered yield metric alongside cash flow and DSCR so users can separate property performance from loan structure.
How investors usually interpret the result
| Result pattern | What it usually means | Why it matters |
|---|---|---|
| Lower cap rate | Pricing is rich relative to NOI, or the market is appreciation-driven | You need stronger financing discipline because yield alone is thinner |
| Market-range cap rate | The property is closer to typical local pricing for its income | This is most useful for comparing similar deals in the same market |
| Higher cap rate | Income looks strong relative to price, but risk or quality may also be higher | A higher number is not automatically a better investment |
Formula and variables
Where:
- Annual NOI
- Net operating income — gross rent × (1 − vacancy) minus recurring expenses and reserve-style allowances, excluding the mortgage
- Purchase Price
- Total acquisition cost of the property
Example:
- Annual NOI = $18,000
- Purchase Price = $300,000
- Step 1: Cap Rate = 18,000 ÷ 300,000
- Step 2: Cap Rate = 0.060 = 6.0%
A 6% cap rate means the property generates $6 of income per $100 of value, before any financing costs.
What strong vs weak results usually mean
Stronger result: A useful cap rate is market-aware. In some cities a 6% cap rate is competitive; in others it signals unusual risk. The number only matters when paired with local context and realistic NOI assumptions.
Weaker result: A weak cap rate interpretation usually means someone is comparing properties without verifying the NOI. Inflated rent or missing reserves can make a mediocre deal look artificially strong.
- Use cap rate to compare properties before financing.
- Validate the NOI line items behind the cap rate.
- Pair cap rate with cash flow and DSCR before making a decision.
Example analysis
A property with $18,000 annual NOI and a $300,000 purchase price has an estimated 6.0% cap rate.
This is the point of an underwriting calculator: one number should always be traceable back to its underlying assumptions. If the output changes after a small rent, expense, or financing update, that is not noise. It is the deal showing you where the real sensitivity lives.
Common mistakes
- Treating cap rate as a financing metric.
- Comparing cap rates without validating the NOI assumptions.
- Assuming a higher cap rate always means a better investment.
Related FAQs
Related resources
Why this metric should not stand alone
No serious rental property decision should rely on a single output. A cap rate without financing context, a mortgage payment without operating expenses, or a DSCR without rent validation can all point investors in the wrong direction.
The practical goal is not to memorize formulas. It is to understand which assumption changed, whether that change is realistic, and how the full deal behaves once the inputs are connected.
Analyze your own deal
See this metric in context with your purchase price, rent, expenses, and financing assumptions.
Analyze your own dealDealPrism provides educational analysis based on available data and user assumptions. Results are estimates and may change if rent, taxes, insurance, financing, or other inputs are updated. This content is not financial, legal, tax, or investment advice.