Total monthly cost of ownership
Cost to Own a Home in Key Biscayne, Florida
A $1,239,000 home here costs
$9,188per month, all in — with 20% down at today's 6.66% 30-year fixed rate.
A standard mortgage calculator would have told you $6,370. The real number is $2,819 higher every month — 44% more than the payment most buyers budget for.
Where every dollar goes
Only the first line is a mortgage payment. Change any assumption above and every figure below recalculates.
Key Biscayne against Miami-Dade County and Florida
| Measure | Key Biscayne | Miami-Dade County |
|---|---|---|
| Median home value | $1,238,700 | $425,400 |
| Median property tax | $10,001 | $3,516 |
| Effective tax rate | 0.807% | 0.827% |
| Median gross rent | $3,501 | $1,731 |
| Population | 14,560 | 2,685,296 |
The weather behind that power bill
Key Biscayne sits in Miami-Dade County, which averages a high of 91.7°F in its hottest month and a low of 56.8°F in its coldest, with 56.08" of precipitation a year and 43% of it in a single three-month stretch. That climate drives 4,244 cooling and 156 heating degree days, which is what sets the $136 electricity line above.
See the full climate breakdown for Miami-Dade County — month by month temperatures, rainy season timing, snowfall and heating and cooling costs.
Other cities in Miami-Dade County
Full Miami-Dade County cost breakdown · Every county in Florida
Common questions
How much does it cost to own a home in Key Biscayne?
A $1,239,000 home in Key Biscayne, Florida costs approximately $9,188 per month with 20% down at 6.66%. That is $6,370 principal and interest, $833 property tax, $749 homeowners insurance, $204 utilities and $1,033 set aside for maintenance.
What is the property tax rate in Key Biscayne?
Key Biscayne has an effective property tax rate of 0.807%, based on a median home value of $1,238,700 and median real estate taxes of $10,001. That is lower than the Miami-Dade County average of 0.827%.
What is the average home price in Key Biscayne?
The median owner-occupied home value in Key Biscayne, Florida is $1,238,700, against $425,400 across Miami-Dade County.
Is it cheaper to rent or buy in Key Biscayne?
Median gross rent in Key Biscayne is $3,501 a month, against $9,188 to own the median home all in. Renting costs less month to month here, though renting builds no equity.
Sources & methodology
- Median home value, real estate taxes, gross rent and population for Key Biscayne — US Census Bureau, American Community Survey ACS 2023 5-Year, place-level tables.
- Homeowners insurance — NAIC average premium for Florida.
- Electricity price — EIA Electric Power Monthly Table 5.6.A.
- Mortgage rate — Freddie Mac PMMS, refreshed weekly.
- Maintenance (1%/yr) and water and sewer ($68/mo) are national estimates. Every assumption above is editable.