238 Buttonwood Dr
Key Biscayne, FL 33149 · single_family · For Sale · 104 days on market
Asking price$8,500,000
6 beds 7 baths 4,190 sqft
Suggested offer$6,582,741$1,917,259 above the est. market value of $6,582,741.
View on Realtor.com →Listed by Fernanda Moreno Harcha · Douglas Elliman - 5555 Biscayne Blvd
Typesingle_family
Built2026
Price / sqft$2029
Est. value (own analysis)$6,582,741
Rent estimate (own analysis)$21,500/mo
HOANone
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Statusfor_sale
Listed date2026-05-21
Removed date—
MLSMiamiMLS #A12021891
Coordinates25.69694, -80.16802
Address238 Buttonwood Dr
CityKey Biscayne
StateFL
Zip33149
Listing ID9233648268
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 | $8,500,000 |
| Down payment (20.0%) | $1,700,000 |
| Loan amount | $6,800,000 |
| Closing costs (5.0%) | $425,000 |
| Total cash to close | $2,125,000 |
| Income | |
| Rent (comp-derived) | $21,500$258,000 |
| Vacancy loss (8.0%) | |
| Effective gross income | $19,780$237,360 |
| Operating expenses | |
| Property tax (placeholder 1.9% of price) | $13,458$161,500 |
| Insurance (placeholder 0.8% of price) | $5,667$68,000 |
| HOA dues | $0$0 |
| Management (0.0% of EGI) | $0$0 |
| Maintenance (5.0% of GSR) | $1,075$12,900 |
| Total operating expenses | $20,200$242,400 |
| 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) | $1,075$12,900 |
| 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 | 5 | 3,356 | $21,400 | 2026-02-06 | — | |
| single_family | 6 | 6 | 4,007 | $27,000 | 2026-08-05 | — | |
| single_family | 6 | 9 | 4,757 | $21,500 | 2026-03-02 | — |
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 | — |
| 420 Island Dr | single_family | 6 | 8 | 6,405 | $12,485,000 | — |
| 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 | — |
| 544 Warren Ln | single_family | 6 | 6 | 1,044 | $8,000,000 | — |
10-year hold projection
IRR-7.2%
Equity multiple-0.20x
Total return (10yr)-$1,447,428
| Year | Property value | NOI | Cash flow | Loan balance | Equity |
|---|---|---|---|---|---|
| 1 | $8,755,000 | -$5,040 | -$542,324 | $6,726,273 | $2,028,727 |
| 2 | $9,017,650 | -$3,979 | -$541,585 | $6,647,483 | $2,370,167 |
| 3 | $9,288,180 | -$2,856 | -$540,793 | $6,563,282 | $2,724,897 |
| 4 | $9,566,825 | -$1,669 | -$539,944 | $6,473,300 | $3,093,525 |
| 5 | $9,853,830 | -$413 | -$539,036 | $6,377,138 | $3,476,692 |
| 6 | $10,149,445 | $912 | -$538,067 | $6,274,372 | $3,875,072 |
| 7 | $10,453,928 | $2,311 | -$537,033 | $6,164,550 | $4,289,378 |
| 8 | $10,767,546 | $3,785 | -$535,932 | $6,047,185 | $4,720,360 |
| 9 | $11,090,572 | $5,340 | -$534,761 | $5,921,762 | $5,168,810 |
| 10 | $11,423,289 | $6,977 | -$533,517 | $5,787,725 | $5,635,564 |
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.