Enter your lot size, existing structures, and proposed project. We calculate your current lot coverage, check it against your county’s actual limit, and tell you exactly how much square footage you have left — or how far over you are.
Select your state, county, and zoning district. The calculator loads your county's actual lot coverage limit — not a generic estimate.
Enter your lot size, then add every existing structure and hard surface. The running total updates as you type.
Add what you want to build — pool, deck, addition, ADU, shed. The calculator shows whether it fits within your limit, by exactly how many square feet.
The calculation table in the results is formatted exactly as it must appear on your permit site plan. Copy it directly from the tool.
Lot Dimensions
| # | Description | Width (ft) | Depth (ft) | Area (sq ft) | |
|---|---|---|---|---|---|
| Total Existing Impervious Area: | 0 sq ft | ||||
| # | Description | Width (ft) | Depth (ft) | Area (sq ft) | |
|---|---|---|---|---|---|
| Total Proposed Area: | 0 sq ft | ||||
Instant results · No signup required · All calculations run in your browser
Coverage vs. Maximum Allowed
Coverage Breakdown
| Description | Type | Dimensions | Area (sq ft) | % of Lot |
|---|
Whether your property passes or fails, we prepare county-specific, permit-ready site plans that include the verified lot coverage table your building department requires — formatted, stamped, and delivered in 12–24 hours.
Enter your details below and we'll send your complete lot coverage report — plus a free consultation on your permit site plan needs. We also send a copy to our team so we can follow up with personalized advice.
We send a copy to drafting@siteplans.online so our team can follow up with a personalised site plan quote for your property.
Your lot has a maximum percentage that can be covered by structures and hard surfaces. This limit — called lot coverage or impervious surface coverage — exists so that enough of your property remains open for drainage, air circulation, and neighborhood character.
Every building department in the United States checks this before issuing a permit.
The formula is simple:
Lot Coverage % = (Total Covered Area ÷ Total Lot Area) × 100
If your county allows 40% maximum and you are already at 35%, you have 500 sq ft of coverage remaining. A 14 × 28 ft pool adds 392 sq ft of water surface — plus however much deck surrounds it. A 500 sq ft addition takes you to exactly the limit. A 600 sq ft deck takes you over.
Knowing this number before you design the project — not after you submit the permit — is the difference between a smooth approval and a correction notice.
This is where most homeowners get surprised. The coverage calculation is not just the house footprint.
No single national lot coverage standard exists. Every state, county, and city sets its own rules. Here are the limits for our most active markets.
Florida has no statewide lot coverage limit. Each county and city sets its own. Limits in our most active Florida markets:
| County | RS-1 Zone | RS-2 / R-1 Zone | Key Note |
|---|---|---|---|
| Miami-Dade | 30% | 35% | HVHZ — F.S. 515.29 pool barrier required |
| Broward | 35% | 40% | HVHZ — pool barrier 60 inches minimum |
| Palm Beach | 30% | 35% | ePZB portal — 3 separate jurisdictions |
| Hillsborough / Tampa | 35% | 40% | City vs County — verify jurisdiction |
| Orange County | 35% | 40% | FastTrack portal — file naming rules |
| Lee County | 35% | 40% | #1 FL permit volume — 8,774 permits/2025 |
| Pinellas (St. Pete) | 35% | 40% | St. Pete pool side setback: 7 ft (not 5 ft) |
| Collier / Naples | 30% | 35% | City of Naples: PE stamp required for pools |
| Sarasota | 35% | 40% | Shed threshold: 100 sq ft (not 120) |
| Alachua / Gainesville | 35% | 40% | Active ADU market post SB 943 |
California residential zones (R-1, RS-1) typically allow 40–50% lot coverage. Critical 2026 rule: ADUs up to 800 sq ft are exempt from local lot coverage limits under state law (AB 68) — local governments cannot use lot coverage to deny a conforming ADU.
| City / County | Typical RS-1 Limit | ADU Exception |
|---|---|---|
| Los Angeles | 40% | ADUs ≤800 sq ft exempt — AB 68 |
| San Diego | 40% | ADUs ≤800 sq ft exempt |
| San Jose | 40% | State ADU preemption applies |
| Sacramento | 45% | State ADU preemption |
| Riverside | 40% | Seismic Zone 4 — CBC required |
Texas has no statewide lot coverage law. Houston has no citywide zoning ordinance — lot coverage limits come from deed restrictions recorded with Harris County, not a zoning map.
| City / County | Typical Limit | Key Note |
|---|---|---|
| Houston / Harris County | 35–45% (deed) | No zoning — verify deed restrictions |
| Dallas | 45% | Dallas Development Services |
| Austin / Travis County | 40% | HOME Initiative — up to 3 units |
| San Antonio / Bexar | 45% | Bexar County Development Services |
| Fort Worth / Tarrant | 40% | Fastest growing US major city |
Georgia has no statewide lot coverage law and no statewide ADU legislation. Rules are entirely local.
| County / City | Typical Limit | Key Note |
|---|---|---|
| Atlanta (R-4) | 50% | Office of Buildings |
| DeKalb County | 35% | Separate from City of Atlanta |
| Gwinnett County | 35–40% | Fastest growing GA county |
| Cobb County | 35–40% | City of Marietta: separate jurisdiction |
| Savannah / Chatham | 35–45% | Historic district overlay review |
It depends on the jurisdiction — and the difference can mean several hundred square feet. Permeable pavers allow water to pass through the surface rather than running off as impervious surface. In some counties, this means they're excluded from the calculation.
| Jurisdiction | Permeable Paver Treatment |
|---|---|
| Miami-Dade (HVHZ) | Counted — same as concrete |
| Broward County | Counted in most zones |
| Orange County FL | Often excluded — document on plan |
| Austin TX | May be excluded — confirm first |
| Denver CO | Generally excluded |
| Los Angeles CA | Varies by district |
In order of how most homeowners handle it:
The fastest solution. Shrink the proposed project so the new total stays within the limit. For a pool: reduce from 16×32 to 14×28. For a deck: remove 100 sq ft from one side. For an addition: narrow by one room.
The calculator shows you exactly how many square feet you need to remove. Use that number to brief your contractor before finalizing the design.
Remove an existing patio, driveway section, old shed, or concrete walkway. Every square foot you remove creates room for your new project. Many homeowners have unused concrete from a previous owner's project they can demolish.
A formal application to your county's zoning board requesting permission to exceed the lot coverage limit. Requires: written application, evidence of hardship, often a public hearing, zoning board vote.
Timeline: typically 8–16 additional weeks. Cost: filing fees plus any attorney or consultant fees. Not guaranteed.
Best when excess is under 5% with a clear hardshipIn counties that exclude certified permeable paving systems from the impervious surface calculation, replacing concrete with permeable pavers can reduce your calculated coverage.
Verify with your county before ordering materials — not all jurisdictions offer this exclusion.
Building departments don't just want to see the calculation — they want it on the drawing itself, in a specific format, showing specific numbers. A note that says "lot coverage complies" without the table is a correction notice.
Every site plan we prepare includes the lot coverage calculation table formatted directly on the drawing. This is the format building departments across Florida, California, Texas, and Georgia accept:
LOT COVERAGE CALCULATION ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Total Lot Area: 10,000 sq ft ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ EXISTING COVERAGE: House footprint: 2,000 sq ft Attached garage: 440 sq ft Concrete driveway: 720 sq ft EXISTING TOTAL: 3,160 sq ft (31.6%) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ PROPOSED ADDITION: Pool (14×28): 392 sq ft Pool deck: 500 sq ft PROPOSED TOTAL: 892 sq ft ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ NEW TOTAL: 4,052 sq ft (40.5%) MAXIMUM ALLOWED (RS-2): 50.0% STATUS: ✅ COMPLIES ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
The calculator above generates this table automatically. Copy it from the results screen — it's in the exact format building departments accept.
Your permit site plan includes this table as part of the standard drawing. You never calculate it manually.
Estimate your permit site plan price in 4 steps.
What does your county require for your project?
Got a correction notice? See what to fix.
Verify your plan before submitting it.
Does your Florida lot qualify under SB 943?
Every site plan we prepare includes the lot coverage calculation — automatically. You never calculate it yourself. We verify your lot area from GIS parcel records, check your county's exact zoning limit, and format the table on the drawing in the format your building department requires.
From $79 · 12–24 hour delivery · All 50 states · Free revisions · FBPE License #55163
This calculator provides estimates for planning purposes only. Results are based on typical zoning standards and may not reflect the exact requirements of your specific parcel, zoning district, or local building department. Always verify lot coverage requirements with your local building or planning department before submitting a permit application. This calculator does not constitute legal, engineering, or professional permitting advice.
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