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    Charming Duplex in Old Town Title is generated by Realmo AI

    606 Grinnell Street, Key West, FL 33040

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    Claim this Listing
    For Sale
    $1,750,000

    Key West duplex with flexible living and investment potential.

    Type:Multi-Family
    Property size:
    1,870 SF
    Price / SF:
    $935/SF
    Added:
    May 17, 2026
    Days on Market:
    17
    Last Refresh:
    May 27 at 7:38 am

    Property Features for 606 Grinnell Street

    General Information

    Standard status
    Active
    Size
    1,870 SF
    Property subtype
    Multi-Family

    Building Details

    Year Built
    1901

    We can help!

    Listing Contact
    Christopher Orth

    Listing agent Christopher Orth License #3275955

    Listing office Berkshire Hathaway HomeServices Knight & Gardner Realty

    Listing date May 17, 2026

    Source Xome

    Displayed information is deemed reliable but is not guaranteed and should be independently verified.

    All listing content including descriptions, pricing, images are the copyrighted material of Berkshire Hathaway HomeServices Knight & Gardner Realty

    HighLights

    • Located in the heart of Old Town Key West.
    • Private backyard with a pool.
    • Duplex offers flexible living opportunities.
    • First‑floor unit: 2 bedrooms, 1.5 baths; Second‑floor unit: 3 bedrooms, 1 bath with private balcony.
    • Both units have full‑sized kitchens, dining spaces, and living rooms.
    • Moments from Duval Street, historical seaport, shopping, and nightlife.

    Overview

    Located in the heart of Old Town Key West, 606 Grinnell Street is a charming duplex offering flexible living opportunities. The first-floor unit features 2 bedrooms and 1.5 baths. The second-floor unit offers 3 bedrooms and 1 bath, complete with a private rear balcony overlooking the backyard. Both units include full-sized kitchens with dining spaces, as well as living rooms. A front porch enhances the home's island charm. The property includes a backyard retreat featuring a pool. This Old Town property offers potential for investment, multi-generational living, or the option to live in one unit while renting the other. The property has a side door entrance for the second unit and a lockout door in the first unit for optional access to the upstairs unit. The property is located moments from Duval Street, the historical seaport, shopping, and nightlife experiences. The property size is 1870 square feet.
    Location Intelligence

    Current Use by Public Records

    Hidden Key West ... Travel Agency

    Suggested Use

    Law Firm Restaurant Real Estate Agency Spa & Massage Center Dental Office Hair Salon Nail Salon Food Market Pharmacy Daycare Center

    Zoning and permitted uses should be independently verified with local authorities.

    Location Insight

    • Map
    • Local Demand
    City
    Key West
    County
    Monroe
    State
    Florida
    Longitude
    -81.7962465
    Latitude
    24.5581262

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    FAQs

    What type of property is this?
    Duplex - Key West duplex with flexible living and investment potential.
    Where is this duplex located?
    The property is located at 606 Grinnell Street Key West, FL.
    What is the asking price?
    The asking price for this property is $1,750,000.
    What are key features of this property?
    This property features: Located in the heart of Old Town Key West.; Private backyard with a pool.; Duplex offers flexible living opportunities.
    (305) 294-5155
    We can help!
    Listing Contact
    Christopher Orth
    Real Estate License ID: 3275955
    Learn More
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    Realmo Value Estimations

    Realmo estimates a property’s market value using a proprietary methodology that incorporates public data and user-submitted information. This cumulative value is generated by integrating a variety of conventional and innovative methods. 

    Disclaimer

    These figures are not official appraisals and should not be used as a substitute for a valuation performed by a licensed appraiser.
    Actual market value may differ due to factors not captured in the data. Estimates are offered for informational purposes only, and users should conduct independent research before making financial or investment decisions.
    By using this feature, you acknowledge that Realmo is not responsible for actions taken based on these estimates.

    AI approach

    Realmo AI Method estimates property value using machine learning models trained on millions of comparable listings, transactions, and market signals. It analyzes property features, location intelligence data, and current market dynamics to predict the most probable market value in real time.

    Realmo CapRate Calculation

    Realmo calculates the Capitalization Rate (Cap Rate) to help estimate a property's potential return on investment. The Cap Rate is a fundamental metric in commercial real estate that measures the relationship between a property's net operating income and its market value.

    How We Calculate Cap Rate

    Cap Rate Formula:
    Cap Rate (%) = (Net Operating Income / Property Value) × 100

    Net Operating Income (NOI) Formula:
    NOI = Area × Lease Rate × (1 - Vacancy Rate) × (1 - Operating Expense Ratio)

    Components

    Net Operating Income (NOI) represents the annual income a property generates after operating expenses:

    • Area: Building square footage from property records
    • Lease Rate: Annual $/sqft based on market data for the property type and geographic location
    • Vacancy Rate: Percentage of unoccupied space based on market data for the property type and location
    • Operating Expense Ratio: Operating costs as a percentage of income, varies by property type

    Property Value is derived from:

    • Recent sale price (if available)
    • Statistical models using comparable sales
    • AI-powered valuation estimates

    Example Calculation

    For a 100,000 sqft Office Building:

    • Lease Rate: $25.00/sqft/year (market data for Office in this area)
    • Vacancy Rate: 8% (market data for Office in this area)
    • Operating Expense Ratio: 35% (typical for Office properties)
    • Property Value: $15,000,000

    Step 1: Calculate NOI

    NOI = 100,000 × $25.00 × (1 - 0.08) × (1 - 0.35)
    NOI = 100,000 × $25.00 × 0.92 × 0.65
    NOI = $1,495,000/year

    Step 2: Calculate Cap Rate

    Cap Rate = ($1,495,000 / $15,000,000) × 100
    Cap Rate = 9.97%

    Property Type Considerations

    Net Operating Income calculations vary by property type due to different operating expense ratios:

    • Office: Higher expenses (30-40%) for HVAC, utilities, maintenance
    • Retail: Moderate expenses (25-35%) for common area maintenance
    • Industrial/Warehouse: Lower expenses (15-25%) for minimal tenant services
    • Multifamily: Moderate expenses (35-45%) including property management
    • Self-Storage: Lower expenses (25-35%) due to minimal maintenance

    Market lease rates and vacancy rates are specific to each property type and geographic location, reflecting local market conditions.

    Disclaimer

    These calculations are estimates for informational purposes only and should not be used as a substitute for professional financial analysis or appraisal.

    • Cap Rate calculations depend on market data that may change over time
    • Actual operating expenses, lease rates, and vacancy rates may differ from market averages
    • Individual property conditions, lease terms, and tenant quality significantly impact actual NOI
    • Property value estimates are approximations and not official appraisals
    • Cap rates vary widely by market, property condition, and investment risk profile

    Professional Guidance Recommended: Before making any investment or financial decisions, consult with licensed appraisers, commercial real estate brokers, and financial advisors who can evaluate your specific property and circumstances.
    By using this feature, you acknowledge that Realmo is not responsible for investment decisions or actions taken based on these estimates.

    Cap approach

    Capitalization Method calculates value based on estimated net operating income (NOI) and applying a market-based capitalization rate (cap rate), we estimate what a typical investor might be willing to pay for it.

    Comparable approach

    Comparable estimate is based on recent sales of similar nearby properties, adjusted for factors like size, condition, and location.

    Relative

    Relative property class coefficient uses factors that account for typical price differences between various asset types (e.g., retail vs. industrial) to provide a more accurate market-aligned estimate.

    Geo

    Comparable Sales Method, enhanced by Geo coefficients — location-based adjustment factors that reflect differences in price levels across neighborhoods, cities, or regions ensuring a more accurate, market-sensitive valuation.

    Stat Estimate

    This method estimates value based on actual market adjusted recent (~5 years) sales of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all similar sales ($/sqft) are above this value
    • Range-to: 75% of all similar sales ($/sqft) are below this value
    AI Estimate

    This method estimates value based on AI market estimation of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all estimations ($/sqft) are above this value
    • Range-to: 75% of all estimations ($/sqft) are below this value
    Alternative use

    Estimate considers the property’s potential value if used for a different purpose-based on zoning, demand, and market feasibility.

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