Understand Key Biscayne before you commit to an address
Key Biscayne is fifteen thousand people on a barrier island south-east of downtown Miami, reached only by the Rickenbacker Causeway, with Crandon Park at one end and Bill Baggs at the other. It incorporated in 1991 and runs its own fire department, and its total of 15.5108 mills is the lowest of these twenty-four. Figures are the same two indexes measured the same way in all 24 municipalities here, on Florida's rules including the homestead exemption. It is one of only five municipalities in the county that run their own fire department, and so pays none of the county's Fire Rescue district levy.
The cost of living in Key Biscayne, and what a home costs
Two calculators on Florida's own rules: monthly compounding and the month private mortgage insurance stops, and the closing costs this state actually charges.
Rent or buy in Key Biscayne
Whether buying here beats renting, and the year it turns over. Association fees and reserves move faster than price here, and both are figures you can edit.
Mortgage calculator
Monthly compounding, the 30-year fixed loan, the private mortgage insurance a low down payment triggers, and Florida's documentary stamp and intangible taxes on the loan itself.
Then work out whether Key Biscayne is the right part of the county
No neighborhood guides for Key Biscayne yet. What is here instead is the county on one comparable footing.
All 24 municipalities in Miami-Dade
Every municipality side by side on home value, millage, the rate a homesteaded buyer pays, and which five run their own fire departments.
Compare the countyBoca Raton and the Palm Beach coast
The same state, the same exemptions and the same two Zillow indexes in the same month, and, counter to what almost everyone assumes, a higher average insurance premium than Miami-Dade's.
Compare the two coastsMiami, neighborhood by neighborhood
One of the two municipalities here with sourced guides rather than a single row of figures. What each part of the city costs and is like to live in, dated and cited.
Explore MiamiHialeah, area by area
The other municipality here with a hub of its own: the same row of figures as this table, the city in five areas drawn from its own master plan, and neighborhood guides in a city that runs its own fire department and library.
Explore HialeahWhat buying in Key Biscayne actually involves
The arithmetic here is the pattern that runs through every layer on this site: an extraordinary assessment base needs a low rate. The village's own levy of 2.8846 mills is modest, it pays none of the county's Fire Rescue district levy because it runs its own department, and a homesteaded buyer's effective rate of 1.51% is the second-lowest in this layer. On a typical home value of $1.71 million that is still about $25,900 a year.
The island's constraint is the causeway, and it is not a small one: one road, tolled, with a history of closures and a long-running argument about the bridge's condition and the bike lane's safety. Beyond that this is a barrier island in the most hurricane-exposed county in the continental United States, and the village's own resilience planning (beach renourishment, stormwater, seawall standards) is a permanent municipal preoccupation rather than a project.
The village runs its own police and fire services and its own K-8 school is a significant part of why families are here, which is unusual for a municipality of this size. Those services are the other half of what the low millage buys, and they are worth understanding alongside the tax arithmetic rather than separately from it.
The island is bracketed by two large parks, Crandon at one end and Bill Baggs at the other, so the developable land is fixed and has been for decades. That constraint is most of why values sit where they do, and it also means beach renourishment, dune maintenance and erosion are village-level questions with direct effects on individual streets.
Moving to Key Biscayne: check these before you commit
- The Rickenbacker Causeway's condition, tolls and closure history, since it is the only way on and off.
- Flood elevation and seawall standards, which the village has been tightening.
- For condominiums: reserve funding and milestone inspection status, as everywhere in this county.
- Beach renourishment and erosion in front of the specific stretch, which the village funds and manages.
- The village's own school and its enrolment, if that is part of why you are buying here.
Key Biscayne levies 2.8846 of the 15.5108 mills charged here. The rest is Miami-Dade County, the school district and the countywide districts: none of which the municipality sets.
Sourced, dated, and separated from the guesswork
Every Key Biscayne figure below is cited, stamped with the period it describes, and editable, because a number for the whole city rarely describes your purchase. Appreciation and investment returns are assumptions rather than facts, and they are labelled that way. Read the methodology for how the line is drawn.
- Prices, rents and tax rates: published statistics and the official schedules.
- Nothing here is a lender quote, a pre-approval or financial advice.
Where the Key Biscayne figures come from
- Zillow Home Value Index (ZHVI), all homes, mid-tier, smoothed and seasonally adjusted: city file, June 2026 · Zillow Research · retrieved Supports: A typical home value for the 35th to 65th percentile of each municipality's market, computed on one method across all twenty-four, The same series and month the Charlotte, Orlando and Palm Beach pages use, so all four American layers can be read against each other, Year-over-year change to June 2026
- Zillow Observed Rent Index (ZORI), all homes, smoothed: city file, June 2026 · Zillow Research · retrieved Supports: Asking rents across the whole rental stock for the twenty-two municipalities Zillow indexes
- Table 1: Comparison of Taxes Levied, county and municipal governments, fiscal years 2024-25 and 2025-26: Miami-Dade · Florida Department of Revenue, Property Tax Oversight · retrieved Supports: The adopted 2025-26 millage rate for Miami-Dade County and every municipality in it, The county's own components: countywide 4.5740, Fire/Rescue 2.3965, Library 0.2812 and the Unincorporated Municipal Service Area at 1.9090, Municipal rates from Sunny Isles Beach's 1.7000 to Biscayne Park's 9.3000
- 2025 millage rates and taxing authorities, Miami-Dade County · Miami-Dade County Property Appraiser · retrieved Supports: A published combined rate for unincorporated Miami-Dade of 16.9317 mills, Its components: school district 6.4990, countywide 5.7361, regional water districts 0.3911, Fire Rescue 2.3965 and UMSA 1.9090, which this layer's stack reproduces exactly, Millage code 0100, the City of Miami, at 19.9878 mills for 2025: 7.1080 of city operating levy and 0.2536 of city debt service on the countywide 12.6262, Opa-locka's municipal operating levy of 8.9797, and a 2025 total of 24.0024 for millage code 0800, A city debt service column, which nine of the twenty-four municipalities here carry: Miami 0.2536, Miami Beach 0.2779, North Bay Village 1.1666, Golden Beach 0.6000, Miami Shores 0.1331, North Miami Beach 0.2000, Miami Gardens 0.4331, Doral 0.4810 and Homestead 0.2446, A blank library district column for Hialeah, North Miami, North Miami Beach, Homestead, Miami Shores, Bal Harbour and Surfside, which are outside the county library district, A blank Fire Rescue column for Miami, Miami Beach, Coral Gables, Hialeah and Key Biscayne, which is the five this layer flags
- Documentary stamp tax · Florida Department of Revenue · retrieved Supports: A Miami-Dade deed rate of 60 cents per $100 rather than the 70 cents charged in every other county, A Miami-Dade surtax of 45 cents per $100, not due on a document transferring only a single-family dwelling, 35 cents per $100 on a promissory note, statewide
- Documentary stamp tax · Florida Department of Revenue · retrieved Supports: 70 cents per $100 on a deed, in every county except Miami-Dade, which charges 60 cents plus a 45-cent surtax, 35 cents per $100 on a promissory note or other written obligation to pay money