What Can I Build on My Miami Lot? A Plain-English Guide to Miami 21 Zoning

By Aiden Martinez, founder of Kairos Real Estate Systems · October 2026

If you're looking at a lot in the City of Miami, the first question isn't the price. It's what you're allowed to build there. The answer lives in Miami 21, the city's zoning code. It's a long code with its own vocabulary, so here's a plain-English guide to the parts that matter most when you size up a site.

The short version

Every lot in the City of Miami sits in a "transect" zone. The zone name tells you three things at a glance:

• The T-number (T3 to T6) tells you how urban the area is, from quiet single-family streets (T3) to the high-rise core (T6).
• The number after T6 (T6-8, T6-12, T6-36…) is the maximum height in stories.
• The letter at the end (R, L or O) tells you how much non-residential use is allowed: Restricted (mostly residential), Limited (some commercial), Open (the widest mix).

So T6-12-O means: urban core, up to 12 stories, open to a wide mix of uses.

The zones, one by one

Densities below are the base maximums under Miami 21.

A few things that trip people up:

• Density is per acre. A typical 5,000 SF City of Miami lot is about 0.11 acres. At 36 units/acre (T4) that's about 4 units. At 9 units/acre (T3-R) it's a single home.
• T6 base density can go higher. In some designated areas and with bonus programs, T6 density can go well beyond the 150 units/acre base.
• "By right" vs. permission. Miami 21 marks each use as allowed by right (R), by warrant (W, an administrative approval) or by exception (E, a public hearing). A use that's only allowed by exception is possible but not guaranteed, and it adds months.

What can change the answer

The base zone is the starting point, not always the final word. These can change what you're allowed to build:

1. Overlays and special plans. Some neighborhoods have overlay districts or Special Area Plans with their own rules on height, setbacks or design.
2. Bonus programs. Miami 21 offers extra height or density in exchange for public benefits, like affordable or workforce housing.
3. State law. Florida's Live Local Act lets qualifying affordable-housing projects exceed local density and height limits on certain commercial and industrial land.
4. Pending rezonings. The city rezones areas over time. A lot's zone today may not be its zone next year. Hearings near your lot are worth knowing about before you buy.
5. Lot size. Many zones set a minimum lot size. Older lots that are smaller than today's minimum can sometimes still be built on as "lots of record", but with conditions.

Zoning is only the first question

Knowing what you can build is step one. Before you commit to a site, you also want to know what you'd be walking into: recorded liens or lawsuits against the property, open or expired permits, flood exposure, environmental records, easements, and how the asking price compares to recent sales.

Pulling all of that together normally means days of digging through separate official record systems, or paying someone to do it.

That's why we built Kairos. Enter a City of Miami address and your intended use, and in about a minute you get a clear read on what you can build and what you'd be inheriting, each finding traced to its source. You can see a real example screen at kairosrealestatesystems.com, no sign-up needed, and new accounts get 3 free screens.

This guide is general information about the Miami 21 zoning code, not legal or zoning advice. Zoning rules change and individual lots can have conditions not covered here.