Cap rate in plain English

The capitalization rate (cap rate) is a simple way to express an income property’s annual operating yield before financing. Think of it as: “If I bought this property with all cash, what percentage of my purchase price would I earn each year from operations?”

Cap rate is popular because it’s fast. You can screen many deals quickly and compare properties on a consistent basis. But it’s also limited: it ignores loan terms, taxes on profits, future rent growth, appreciation, and major capital expenditures.

• Effective Gross Income (EGI) = Gross Rent × (1 − Vacancy Rate)
• Net Operating Income (NOI) = EGI − Operating Expenses
• Cap Rate = NOI ÷ Purchase Price
• Max Offer Price (Target Cap) = NOI ÷ Target Cap Rate

• Lower cap rate often means a higher price relative to income (common in prime locations).
• Higher cap rate often means a lower price relative to income (often more risk, more work, or weaker demand).
• Cap rate is best used as a starting filter, not the final investment decision.

Frequently Asked Questions

• Does cap rate include the mortgage?

  No. Cap rate ignores financing. Mortgage payments are “debt service,” not operating expenses.

• What expenses should be included in NOI?

  Operating expenses required to run the property: property management, insurance, property taxes, utilities paid by owner, repairs/maintenance, HOA/condo fees, licensing, and similar items. Do not include mortgage principal/interest or income taxes.

• What’s a “good” cap rate?

  It depends on location, property type, and risk. Prime markets may trade at lower cap rates; riskier or higher-effort deals may need higher cap rates. Use cap rate to compare similar properties in the same market.

• Is cap rate the same as cash-on-cash return?

  No. Cash-on-cash return uses actual cash invested and includes financing (down payment, loan terms, debt service). Cap rate is purely NOI relative to price.

Full guide: formula breakdown, examples, and underwriting tips

If you’re screening real estate investments, cap rate is one of the fastest “first-look” metrics you can use. It answers a simple question: How much operating income does this property produce relative to its price? The trick is that the “operating income” in cap rate is not your rent and it is not your cash flow after the mortgage. It’s Net Operating Income (NOI) — a standardized income measure designed to compare properties apples-to-apples.

Here’s the complete chain from rent to cap rate. Start with Gross Scheduled Rent (what you’d collect if every unit paid every month). Real life includes vacancy, turnover, and occasional non-payment, so investors subtract a vacancy and credit loss allowance. The result is Effective Gross Income (EGI). From EGI, subtract the costs required to operate the property — the expenses you’d still pay even if you owned the building outright (no loan). What remains is NOI.

Finally, cap rate expresses that NOI as a percentage of the purchase price: Cap Rate = NOI ÷ Purchase Price. That’s it. The power is in the standardization: two properties with different sizes, rents, and expenses can be compared if you calculate NOI consistently.

EGI is “rent you can realistically count on.” If a property has $36,000/year in gross rent and you assume 8% vacancy, then EGI is $36,000 × (1 − 0.08) = $33,120. In practice, vacancy can represent actual vacant units, rent concessions, collections issues, and turnover downtime. Many investors use an assumption range (for example 5–10%) unless they have strong evidence the property performs better.

Operating expenses are the costs to keep the property running: property taxes, insurance, repairs/maintenance, utilities paid by the owner, landscaping, property management, HOA, trash, pest control, licensing, and similar items. In commercial underwriting, you’ll often see a detailed expense line-item list and a “T-12” (trailing twelve months) statement. For quick screening, many investors use an expense ratio — an estimated percent of EGI that goes to operating expenses. That’s why this calculator offers both options: enter annual expenses directly, or use the expense ratio slider.

Be careful: the words “expenses” can hide big differences. Some underwriters include a reserve for replacements (capital expenditures), like roofs, HVAC, or major appliances. Others treat that separately from NOI. If you’re comparing cap rates in a market, try to be consistent about what you include. If you’re uncertain, be conservative: slightly higher expense assumptions are safer than optimistic ones.

NOI = EGI − Operating Expenses. If the earlier EGI is $33,120 and annual operating expenses are $12,000, then NOI is $21,120. NOI is the “engine” that drives many real estate valuations — not just cap rate. In fact, the income approach to valuation often uses cap rates to convert NOI into value, which is exactly what the “Target cap → max offer price” section does.

Cap Rate = NOI ÷ Purchase Price. If NOI is $21,120 and purchase price is $350,000, cap rate is 21,120 ÷ 350,000 = 0.06034, or 6.03%. Many investors round to one decimal place (6.0%), but for decision-making it can help to keep a little precision.

Imagine a rental home priced at $300,000 with gross rent of $2,200/month ($26,400/year). You assume 7% vacancy, so EGI is $26,400 × 0.93 = $24,552. If your operating expenses are $8,200/year (taxes, insurance, repairs, management), NOI is $24,552 − $8,200 = $16,352. Cap rate is $16,352 ÷ $300,000 = 5.45%. If your target cap is 6.5%, the max offer price would be $16,352 ÷ 0.065 ≈ $251,569. That doesn’t mean the deal is “bad” — it means the price is high relative to NOI given your assumptions and target.

Suppose a duplex collects $48,000/year in rent. You use 5% vacancy → EGI = $45,600. If you estimate a 35% expense ratio, operating expenses = 0.35 × 45,600 = $15,960, so NOI = $29,640. If the seller wants $520,000, cap rate is $29,640 ÷ $520,000 = 5.70%. If similar buildings in that neighborhood trade around 6.0–6.25%, you might negotiate price or verify whether expenses are overstated/understated.

Value-add deals often have two cap rates: “in-place cap” (based on current NOI) and “stabilized cap” (based on expected NOI after renovations, lease-up, or rent increases). Be explicit about which one you’re using. A property might look unattractive on in-place cap but attractive on stabilized cap if your business plan is realistic. The danger is assuming a future NOI that doesn’t materialize — that’s why conservative vacancy and expense assumptions matter.

• Compare like-with-like: cap rates differ by property type, tenant quality, lease terms, and market.
• Don’t ignore taxes/insurance: these can vary drastically by county and can change after a sale.
• Separate capex from opex: roof/HVAC replacements can crush returns if you pretend they don’t exist.
• Check rent realism: “pro forma” rent should match comps, not wishful thinking.
• Use it as a filter: cap rate helps you prioritize which deals deserve deeper analysis.

• Include: property management, insurance, property tax, utilities owner pays, repairs, HOA, admin costs.
• Exclude: mortgage principal/interest, income taxes, depreciation, and one-time purchase closing costs.
• Depends: capital reserves (many investors subtract a reserve; some keep it separate from NOI).

Bottom line: cap rate is a powerful shorthand, but it becomes meaningful only when your NOI assumptions are realistic. Use the sliders to stress-test vacancy and expenses. If the cap rate swings dramatically with small assumption changes, that’s a sign the deal is “thin” — it might still work, but it needs careful verification.

Deal inputs to verify

Before you trust a cap rate, verify the inputs that matter most. Here’s a practical checklist you can use when you’re evaluating a listing.

• Current rent roll (unit-by-unit) and lease expirations
• Market rent comps and vacancy trends nearby
• Other income (parking, laundry, storage) if applicable

• Property taxes (and how they reassess after purchase)
• Insurance quotes and any flood/wind add-ons
• Utilities responsibility (owner vs tenant)
• Maintenance history + upcoming major repairs
• Property management fee assumptions

• Set your target cap rate and see the max offer price.
• Negotiate price, or verify that NOI can realistically increase.
• Use the saved deals list to compare properties quickly.