420 Island Dr
Key Biscayne, FL 33149 · single_family · For Sale · 460 days on market
Asking price$12,485,000
6 beds 8 baths 6,405 sqft
Suggested offer$10,062,639$2,422,361 above the est. market value of $10,062,639.
View on Realtor.com →Listed by Elena Chacon P.A. · BHHS EWM Realty
Typesingle_family
Built2017
Price / sqft$1949
Est. value (own analysis)$10,062,639
Rent estimate (own analysis)$75,000/mo
HOANone
1 / 83
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Statusfor_sale
Listed date2025-05-30
Removed date—
MLSMiamiMLS #A11812864
Coordinates25.68534, -80.16926
Address420 Island Dr
CityKey Biscayne
StateFL
Zip33149
Listing ID5545045231
Sourceus-real-estate-listings, cached 2026-08-31
ZIP market snapshot (33149)
Typical home value (ZHVI)$1,692,135
Typical rent (ZORI)$7,910/mo
Zillow Research's ZHVI (home value index) and ZORI (rent index) for this ZIP, as of 2026-07 — free published data, refreshed monthly, no RentCast quota spent. "Typical value/rent" is a smoothed index, not a literal median of active listings.
Underwriting (buy-and-hold, default assumptions)
| Acquisition (one-time, not monthly/yearly) | |
| Purchase price | $12,485,000 |
| Down payment (20.0%) | $2,497,000 |
| Loan amount | $9,988,000 |
| Closing costs (5.0%) | $624,250 |
| Total cash to close | $3,121,250 |
| Income | |
| Rent (comp-derived) | $75,000$900,000 |
| Vacancy loss (8.0%) | |
| Effective gross income | $69,000$828,000 |
| Operating expenses | |
| Property tax (placeholder 1.9% of price) | $19,768$237,215 |
| Insurance (placeholder 0.8% of price) | $8,323$99,880 |
| HOA dues | $0$0 |
| Management (0.0% of EGI) | $0$0 |
| Maintenance (5.0% of GSR) | $3,750$45,000 |
| Total operating expenses | $31,841$382,095 |
| Net operating income (NOI) | |
| Debt service & reserves | |
| Debt service (6.66%, avg 30yr rate as of 2026-08-27, 30yr amortizing) | |
| CapEx reserve (5.0% of GSR) | $3,750$45,000 |
| Mortgage insurance (PMI) (0.0% of loan, not required — down payment ≥ 20%) | $0$0 |
| Cash flow |
Cap rate
Cash-on-cash
DSCR
Rent-to-price (1% rule)
Gross rent multiplier
Operating expense ratio
Break-even occupancy
Comparables
Same ZIP. Real active rental listings, used to derive the rent estimate above.
| Address | Type | Beds | Baths | Sqft | Asking rent | Listed | Days on market |
|---|---|---|---|---|---|---|---|
| single_family | 6 | 7 | 8,202 | $368,050 | 2024-04-14 | — | |
| single_family | 6 | 9 | 4,757 | $21,500 | 2026-03-02 | — | |
| single_family | 6 | 7 | 6,433 | $75,000 | 2026-05-26 | — |
Same ZIP & bedroom count. Closed sales from Realtor.com over the last 12 months, matched to this property's type — real transaction prices, not asking prices. Falls back to Miami-Dade County public records (property appraiser tax roll) when Realtor.com has no sales on file for the area.
| Address | Type | Beds | Baths | Living sqft | Sale price | Sale date |
|---|---|---|---|---|---|---|
| 762 Fernwood Rd | single_family | 6 | 5 | 3,584 | $5,690,000 | 2026-06-15 |
| 285 Woodcrest Rd | single_family | 6 | 6 | 3,520 | $6,700,000 | 2026-04-22 |
| 635 Curtiswood Dr | single_family | 6 | 6 | 3,888 | $4,950,000 | 2026-04-20 |
| 180 Cape Florida Dr | single_family | 6 | 8 | 8,031 | $21,000,000 | 2026-02-26 |
| 320 Atlantic Rd | single_family | 6 | 7 | 5,275 | $8,200,000 | 2026-02-25 |
| 320 Woodcrest Rd | single_family | 6 | 5 | 3,737 | $5,220,000 | 2025-10-06 |
Same ZIP. Other properties currently for sale nearby — asking prices, not closed sale prices. Not a price comp; see Sold comps for actual transaction history.
| Address | Type | Beds | Baths | Sqft | Asking price | Days on market |
|---|---|---|---|---|---|---|
| 960 Mariner Dr | single_family | 6 | 10 | 7,742 | $19,500,000 | — |
| 120 Knollwood Dr | single_family | 6 | 7 | 6,208 | $19,950,000 | — |
| 650 Curtiswood Dr | single_family | 6 | 5 | 3,356 | $5,199,000 | — |
| 31 Island Dr | single_family | 6 | 7 | 5,826 | $9,800,000 | — |
| 165 Hampton Ln | single_family | 6 | 9 | 3,842 | $8,250,000 | — |
| 110 Hampton Ln | single_family | 6 | 7 | 3,550 | $6,900,000 | — |
| 238 Buttonwood Dr | single_family | 6 | 7 | 4,190 | $8,500,000 | — |
| 544 Warren Ln | single_family | 6 | 6 | 1,044 | $8,000,000 | — |
10-year hold projection
IRR2.3%
Equity multiple1.37x
Total return (10yr)$2,785,564
| Year | Property value | NOI | Cash flow | Loan balance | Equity |
|---|---|---|---|---|---|
| 1 | $12,859,550 | $445,905 | -$369,322 | $9,879,708 | $2,979,842 |
| 2 | $13,245,337 | $461,193 | -$355,159 | $9,763,979 | $3,481,357 |
| 3 | $13,642,697 | $476,987 | -$340,518 | $9,640,303 | $4,002,393 |
| 4 | $14,051,977 | $493,303 | -$325,384 | $9,508,134 | $4,543,843 |
| 5 | $14,473,537 | $510,160 | -$309,739 | $9,366,889 | $5,106,647 |
| 6 | $14,907,743 | $527,574 | -$293,567 | $9,215,945 | $5,691,798 |
| 7 | $15,354,975 | $545,562 | -$276,851 | $9,054,635 | $6,300,340 |
| 8 | $15,815,624 | $564,145 | -$259,573 | $8,882,248 | $6,933,377 |
| 9 | $16,290,093 | $583,340 | -$241,715 | $8,698,022 | $7,592,071 |
| 10 | $16,778,796 | $603,168 | -$223,258 | $8,501,146 | $8,277,650 |
Assumes 3.0% annual rent growth, 2.5% expense growth, 3.0% appreciation, and a 6.0% selling cost at exit — all placeholder assumptions, not market-derived.