For sale

$1,400,000

Est. $10,486/mo —

•

1,780

sq ft

646 William St, Key West, FL 33040

About this home

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.

Multi-familyProperty Type

1928Year Built

4,116 sq ftLot Size

$787Price/Sq.Ft.

Listed by Louis M Paez • Coldwell Banker Schmitt Real Estate Co. (KW)

Listing updated: Sep 26, 2026 at 01:12pm

Redfin checked: a few seconds ago

•Source:FLKMLS #621406

Payment calculator

$10,486 per month

Principal and interest$7,640

Property taxes

$1,154

HOA dues

Home insurance

$1,692

Utilities

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Open houses

No upcoming open houses.

Nearby open houses (10)

OPEN SAT, 1AM TO 1PM
$825,000
1 bed1 bath400 sq ft
817 Pearl St, Key West, FL 33040
1,101 sq ft lot • Built 1943 • Listed 19 days
OPEN SAT, 8AM TO 10AM3D WALKTHROUGH
$849,000
2 beds1 bath749 sq ft
1116 Eaton St, Key West, FL 33040
1,629 sq ft lot • Pool • Built 1953
OPEN SAT, 11AM TO 1PMVIDEO TOUR
$2,550,000
3 beds3 baths1,902 sq ft
525 Louisa St, Key West, FL 33040
3,390 sq ft lot • 2 parking spots • Pool
OPEN SAT, 11AM TO 1PM
$929,000
2 beds1 bath838 sq ft
3808 Duck Ave, Key West, FL 33040
6,000 sq ft lot • Pool • Built 1958
OPEN SAT, 11AM TO 1PM3D WALKTHROUGH
$2,895,000
3 beds3 baths1,600 sq ft
711 Olivia St, Key West, FL 33040
3,350 sq ft lot • Parking • Pool
OPEN SAT, 11AM TO 1PM3D WALKTHROUGH
$1,725,000
3 beds3.5 baths1,592 sq ft
1105 Watson St, Key West, FL 33040
1,794 sq ft lot • Pool • Built 1943
OPEN SAT, 11AM TO 1PM3D WALKTHROUGH
$1,249,000
2 beds2.5 baths1,387 sq ft
5 Mccoy Cir #5, Key West, FL 33040
$1,377 HOA • 2 parking spots • Pool
OPEN SAT, 11AM TO 1PM3D WALKTHROUGH
$2,434,000
3 beds3 baths2,502 sq ft
1511 17th Ter, Key West, FL 33040
8,250 sq ft lot • Pool • Built 1958
OPEN SAT, 12PM TO 1PM
$849,500
3 beds2 baths1,488 sq ft
2928 Fogarty Ave, Key West, FL 33040
6,621 sq ft lot • Built 1963
OPEN SAT, 12PM TO 2PM
$2,475,000
3 beds2 baths1,750 sq ft
1212 Olivia St, Key West, FL 33040
4,608 sq ft lot • Parking • Pool

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Around this home

Schools

K - 12
Preschool & daycare

Horace O'bryant School

Public PreK-8 • Assigned • 0.7mi

3/10

Key West High School

Public 9-12 • Assigned • 1.3mi

3/10

Provided by GreatSchools

Lifestyle

Provided by Walk Score and Local Logic

Offer insights

646 William St · $1,400,000

Strong offer

$1.4M and above

75% chance or better to win

Why $1.4M+ is a strong offer

DAYS ON MARKET

The average home goes pending in 148 days.

SALE-TO-LIST

Most homes are selling 4% below list price.

About offer insights

Property details

Interior
Exterior
Finance

Kitchen

Bathroom

Bedroom

Living

Interior features
Wood-framed windows
Unfurnished

Bathrooms
2 full bathrooms

Heating & cooling
Hot water heating
Wall/window air conditioning units

Sale and tax history for 646 William St

Sale History
Tax History

Public record

Public record
Zoning
Permits

Beds

Baths

Stories

Lot width

—

Lot depth

—

Lot size

5,070 Sq. Ft.

Year renovated

2002

Finished Sq. Ft.

1,780

Unfinished Sq. Ft.

—

Total Sq. Ft.

1,780

Year built

1928

Style

Multi-Family (5+ Unit)

County

Monroe County

APN

0668 25 00018810000000

Parking Spaces

—

Basement

—

Accessible

—

HOA Dues

—

Garage

—

Features

—

Last updated by owner on Oct 9, 2026.

HHDR

Historic High Density Residential District

The historic high density residential district HHDR is established to implement comprehensive plan policies for areas designated HHDR on the comprehensive plan future land use map. The HHDR district shall accommodate historic high density residential development for permanent residents, including single-family, duplex, and multiple-family residential structures. The purpose of the historic high density residential designation is to provide a management framework for preserving the residential character and historic quality of the Old Town central residential community.; In addition, incidental accessory uses, including duly approved home occupations, and customary community facilities can be located in the HHDR district. The HHDR district shall not accommodate transient residential uses, including guesthomes, motels or hotels. Similarly, the area shall not accommodate freestanding commercial offices, retail, or other commercial uses. Lawfully existing office or commercial uses shall be permitted to continue to exist as lawful nonconforming uses if such uses continue to comply with conditions invoked when the respective uses were approved.

Permitted uses

Include but are not limited to:

Housing-Group
Housing-Single unit
Housing-Multiple units
Cemetery

Climate risks

8/10 Flood Factor

Estimated 80%+ chance of a flood reaching the building in the next 30 years

1/10 Fire Factor

Unlikely to be in a wildfire in next 30 years

Heat Factor

We're working on getting current and accurate heat risk information for this home.

10/10 Wind Factor

99% chance of strong winds in next 30 years

1/10 Air Factor

0 unhealthy days expected this year, 0 days in 30 years

Provided by First Street

Historical weather

Key West, FL • 33040

Average low and high temperatures (°F)

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Sun exposure

87/ 100

Very good sunlight

Sunscore

This home receives average direct sun exposure in Key West. There appears to be minimal shading by surrounding buildings, terrain, and vegetation.

8.8 hrs

6.6 hrs

JuneDecember

Provided by Shadowmap

Redfin Estimate for 646 William St

We cannot show automated home-value estimates for this home.

Nearby homes have recently sold between $1,325,000 and $1,995,000.

Nearby comparable homes

The Redfin Estimate uses 6 recent nearby sales, priced between $1.3M to $2.0M.

SOLD SEP 8, 2026
$1,429,821 Last sold price
4 beds3 baths1,928 sq ft
1421 Reynolds St, Key West, FL 33040
$45/sq ft
30 years newer
SOLD APR 2, 2026
$1,400,000 Last sold price
1 bed1 bath684 sq ft
708 Bakers Ln, Key West, FL 33040
$1260/sq ft
larger lot
44 years newer
SOLD SEP 4, 2026
$1,700,000 Last sold price
4 beds3 baths1,911 sq ft
1407 Petronia St, Key West, FL 33040
$103/sq ft
larger lot
20 years newer
SOLD MAY 22, 2026
$1,325,000 Last sold price
2 beds2.5 baths1,082 sq ft
419 Simonton St Unit A, Key West, FL 33040
$438/sq ft
smaller lot
39 years older
SOLD OCT 22, 2026
$1,650,000 Last sold price
2 beds2 baths1,077 sq ft
907 Frances St, Key West, FL 33040
$745/sq ft
smaller lot
28 years older
SOLD OCT 23, 2026
$1,995,000 Last sold price
2 beds2.5 baths1,409 sq ft
419 Simonton St Unit c, Key West, FL 33040
$629/sq ft
smaller lot
98 years newer

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Details provided by FLKMLS and may not match the public record. Learn more.

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GreatSchools Ratings provided by GreatSchools.org.

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About this home

Payment calculator

Affordability tools

See this home in person

Nearby open houses (10)

Interested in buying?

Around this home

Schools

Lifestyle

Offer insights

Property details

Sale and tax history for 646 William St

Public record

Climate risks

Historical weather

Sun exposure

Redfin Estimate for 646 William St

Early Access listings

Nearby similar homes

New listings for sale in 33040

More real estate resources