644 William Street
The property being sold is 644 William Street. The current property record/card reflects both 644 and 646 William Street, although the property being conveyed is 644 William Street.
The structure at 644 William Street is a two-and-a-half-story home currently configured as a duplex and is in need of renovation.
The first floor consists of two bedrooms and two bathrooms. The second floor contains two bedrooms and one bathroom. A stairwell provides access to the third floor, which is currently unfinished and is not completed or configured as living space.
In its current condition, the property contains four bedrooms and three bathrooms of finished living area, with additional unfinished space on the third floor. The property is currently being used/configured as a duplex and will require renovation.
For sale
$1,400,000
646 William St, Key West, FL 33040
3beds
1,780sqft
Duplex
Built in 1928
-- sqft lot
$-- Zestimate®
$787/sqft
$-- HOA
What's special
Two-and-a-half-story homeThree bathroomsFour bedrooms
- 13 days
- 1,087
- 50
Zillow last checked:
Listing updated:
Listed by:
Louis M Paez 305-395-1081,
Coldwell Banker Schmitt Real Estate Co. (KW)
Source: FLKMLS,MLS#: 621406
Facts & features
Interior
Bedrooms & bathrooms
- Bedrooms: 3
- Bathrooms: 2
- Full bathrooms: 2
Heating
- Has Heating (Unspecified Type)
Cooling
- Wall/Window Unit(s)
Features
- Flooring: Combination
Interior area
- Total structure area: 1,780
- Total interior livable area: 1,780 sqft
Property
Features
- Patio & porch: Open Porch/Balcony
Lot
- Size: 3,920 Square Feet
- Dimensions: 65 X 78
Details
- Parcel number: 00018810000000
- Zoning: HHDR - Historic High Density Residential
Construction
Type & style
- Home type: MultiFamily
- Architectural style: Conch
- Property subtype: Duplex
Materials
- Frame
Condition
- Fixer
- New construction: No
- Year built: 1928
Community & HOA
Community
- Security: No Security
- Subdivision: Old Town - Unlisted (1.0)
HOA
- Has HOA: No
- Services included: None
Location
- Region: Key West
Financial & listing details
- Price per square foot: $787/sqft
- Tax assessed value: $1,567,206
- Annual tax amount: $13,849
- Date on market: 9/25/2026
- Listing terms: Cash,Conventional
Estimated market value
Not available
Estimated sales range
Not available
Not available
Price history
| Date | Event | Price |
|---|---|---|
| 9/25/2026 | Listed for sale | $1,400,000$787/sqft |
Source: | ||
Public tax history
| Year | Property taxes | Tax assessment |
|---|---|---|
| 2025 | $13,850 +12.9% | $1,321,266 +21% |
| 2023 | $12,267 +16.4% | $1,091,955 +10% |
| 2022 | $10,540 +9.6% | $992,686 +10% |
| 2021 | $9,614 +5% | $902,442 +5.5% |
| 2020 | $9,156 | $855,275 +1% |
| 2019 | $9,156 +0.2% | $847,153 -7% |
| 2018 | $9,141 +0.3% | $911,324 -0.2% |
| 2017 | $9,109 +3.2% | $912,984 +23.8% |
| 2016 | $8,829 +7.5% | $737,413 +3.5% |
| 2015 | $8,215 | $712,140 |
Find assessor info on the county website
Monthly payment
Est. payment






