Lot Coverage Calculator
This tool calculates the lot coverage percentage for a property. Lot coverage is the percentage of your lot that is covered by buildings, structures, or other impervious surfaces (depending on local zoning definitions).
Enter the **Total Area of Your Lot** and the **Total Area Covered by All Structures** (including your main house, garage, sheds, etc.) on that lot. Ensure you use consistent units for both area measurements (e.g., square feet, square meters).
Calculate Your Lot Coverage
Understanding Lot Coverage
What is Lot Coverage?
Lot coverage (sometimes called building coverage or impervious coverage, depending on local zoning) is a metric used in urban planning and zoning regulations. It represents the amount of land on a given parcel (lot) that is occupied by structures, which typically includes the main dwelling, garages, sheds, and sometimes even decks, patios, or driveways (check local definitions). It's usually expressed as a percentage of the total lot area.
Why is Lot Coverage Important?
Zoning codes often have maximum lot coverage limits. These limits are in place to manage density, control stormwater runoff (impervious surfaces prevent water absorption), ensure adequate open space and light on properties, and maintain neighborhood character.
Lot Coverage Formula
The calculation is straightforward:
Lot Coverage (%) = (Total Area Covered by Structures / Total Lot Area) * 100
For example, if your lot is 10,000 sq ft and your house and garage cover 2,000 sq ft, your lot coverage is (2000 / 10000) * 100 = 20%.
Lot Coverage Examples
See how lot coverage is calculated in different scenarios:
Example 1: Standard Suburban Lot
Scenario: A suburban home with a main house and detached garage.
1. Known Values: Total Lot Area = 10,000 sq ft, Main House Footprint = 1,800 sq ft, Detached Garage Footprint = 400 sq ft.
2. Total Covered Area: 1,800 sq ft + 400 sq ft = 2,200 sq ft.
3. Formula: Lot Coverage (%) = (Covered Area / Lot Area) * 100
4. Calculation: (2,200 / 10,000) * 100 = 0.22 * 100 = 22%.
Conclusion: The lot coverage is 22%.
Example 2: Small Urban Lot
Scenario: A compact house on a small city lot.
1. Known Values: Total Lot Area = 3,500 sq ft, House Footprint = 1,200 sq ft.
2. Total Covered Area: 1,200 sq ft.
3. Formula: Lot Coverage (%) = (Covered Area / Lot Area) * 100
4. Calculation: (1,200 / 3,500) * 100 ≈ 0.3429 * 100 ≈ 34.29%.
Conclusion: The lot coverage is approximately 34.3%.
Example 3: Large Rural Property
Scenario: A large property with a house and large barn.
1. Known Values: Total Lot Area = 87,120 sq ft (2 acres), House Footprint = 2,500 sq ft, Barn Footprint = 4,000 sq ft.
2. Total Covered Area: 2,500 sq ft + 4,000 sq ft = 6,500 sq ft.
3. Formula: Lot Coverage (%) = (Covered Area / Lot Area) * 100
4. Calculation: (6,500 / 87,120) * 100 ≈ 0.0746 * 100 ≈ 7.46%.
Conclusion: The lot coverage is approximately 7.5%.
Example 4: Property with Shed and Deck
Scenario: A property includes a shed and a covered deck (check local rules if decks count).
1. Known Values: Total Lot Area = 7,500 sq ft, House Footprint = 1,600 sq ft, Shed Footprint = 150 sq ft, Covered Deck Footprint = 200 sq ft.
2. Total Covered Area: 1,600 + 150 + 200 = 1,950 sq ft.
3. Formula: Lot Coverage (%) = (Covered Area / Lot Area) * 100
4. Calculation: (1,950 / 7,500) * 100 = 0.26 * 100 = 26%.
Conclusion: Assuming all structures count, the lot coverage is 26%.
Example 5: Calculating Max Allowed Covered Area
Scenario: You have a 5,000 sq ft lot in a zone with a maximum 30% lot coverage.
1. Known Values: Total Lot Area = 5,000 sq ft, Max Allowed Coverage = 30%.
2. Formula (Rearranged): Max Covered Area = (Total Lot Area * Max Coverage %) / 100
3. Calculation: (5,000 * 30) / 100 = (5,000 * 0.30) = 1,500 sq ft.
Conclusion: The maximum total area you can cover with structures is 1,500 sq ft.
Example 6: Multi-Story Building Footprint
Scenario: Lot coverage only considers the ground-level footprint.
1. Known Values: Total Lot Area = 6,000 sq ft, House Footprint (1st floor area) = 1,800 sq ft (even if it's a 2-story house).
2. Total Covered Area: 1,800 sq ft.
3. Formula: Lot Coverage (%) = (Covered Area / Lot Area) * 100
4. Calculation: (1,800 / 6,000) * 100 = 0.30 * 100 = 30%.
Conclusion: The lot coverage is 30% (regardless of the upper stories). Always use the ground floor footprint.
Example 7: Zero Lot Coverage (Vacant Lot)
Scenario: A vacant piece of land with no structures.
1. Known Values: Total Lot Area = 15,000 sq ft, Total Area Covered by Structures = 0 sq ft.
2. Total Covered Area: 0 sq ft.
3. Formula: Lot Coverage (%) = (Covered Area / Lot Area) * 100
4. Calculation: (0 / 15,000) * 100 = 0 * 100 = 0%.
Conclusion: The lot coverage is 0%.
Example 8: Converting Units (Acres to Sq Ft)
Scenario: You have a 0.5-acre lot and a house footprint of 3,000 sq ft. (1 acre = 43,560 sq ft).
1. Known Values: Total Lot Area = 0.5 acres, House Footprint = 3,000 sq ft.
2. Convert Lot Area to Consistent Units: 0.5 acres * 43,560 sq ft/acre = 21,780 sq ft.
3. Total Covered Area: 3,000 sq ft.
4. Formula: Lot Coverage (%) = (Covered Area / Lot Area) * 100
5. Calculation: (3,000 / 21,780) * 100 ≈ 0.1377 * 100 ≈ 13.77%.
Conclusion: The lot coverage is approximately 13.8%. Always use the same units for both inputs.
Example 9: Attached vs. Detached Garage
Scenario: The garage counts regardless of whether it's attached or detached.
1. Known Values: Total Lot Area = 8,000 sq ft, House Footprint (including attached garage) = 2,200 sq ft, Detached Shed Footprint = 100 sq ft.
2. Total Covered Area: 2,200 sq ft + 100 sq ft = 2,300 sq ft.
3. Formula: Lot Coverage (%) = (Covered Area / Lot Area) * 100
4. Calculation: (2,300 / 8,000) * 100 = 0.2875 * 100 = 28.75%.
Conclusion: The lot coverage is 28.75%. Both attached and detached structures typically contribute to coverage.
Example 10: When Covered Area Equals Lot Area
Scenario: Building covers the entire lot (uncommon due to setbacks and regulations, but mathematically possible).
1. Known Values: Total Lot Area = 4,000 sq ft, Total Area Covered by Structures = 4,000 sq ft.
2. Total Covered Area: 4,000 sq ft.
3. Formula: Lot Coverage (%) = (Covered Area / Lot Area) * 100
4. Calculation: (4,000 / 4,000) * 100 = 1 * 100 = 100%.
Conclusion: The lot coverage is 100%.
Important Considerations
Zoning definitions of "covered area" or "impervious surface" can vary significantly by municipality. Always check your local zoning ordinance for precise definitions regarding what counts towards lot coverage (e.g., paved driveways, patios, swimming pools, pergolas, eaves, etc.). This calculator provides a general percentage based on your direct input of total covered area.
Frequently Asked Questions about Lot Coverage
1. What is Lot Coverage?
Lot coverage is the percentage of your property's total area that is occupied by buildings and other structures, as defined by local zoning rules.
2. How is Lot Coverage Calculated?
It's calculated by dividing the total ground-level area covered by structures (like your house, garage, sheds) by the total area of your lot, and then multiplying by 100 to get a percentage.
3. Why do zoning regulations limit Lot Coverage?
Limits help control density, manage stormwater runoff, ensure sufficient light and air between buildings, and preserve open space and neighborhood aesthetics.
4. Does a multi-story building count its upper floors towards Lot Coverage?
No, typically lot coverage is based only on the ground-level footprint of the structure.
5. Do detached garages or sheds count towards Lot Coverage?
Yes, usually all accessory structures with a roof (like detached garages, sheds, carports) contribute to the total covered area calculation.
6. Do decks, patios, or driveways count towards Lot Coverage?
This varies by municipality and the specific zoning definition. Some codes use "building coverage" (only structures with roofs), while others use "impervious surface coverage" which includes paved areas, concrete patios, etc. Always check your local ordinance.
7. What units should I use for the calculator?
Use any consistent unit for both inputs (Total Lot Area and Total Covered Area), like square feet (sq ft) or square meters (sq m). The result will be a percentage.
8. How can I find my property's Lot Area and Covered Area?
Lot area is typically found on your property deed, plat map, or local assessor's office records. Covered area usually requires measuring the exterior dimensions of all structures at ground level.
9. What happens if my Lot Coverage exceeds the zoning limit?
Exceeding the limit can prevent you from getting building permits for additions or new structures. You may need variances or adjustments to your plans to comply with regulations.
10. Is Lot Coverage the same as Floor Area Ratio (FAR)?
No. Lot Coverage is about the footprint on the land. Floor Area Ratio (FAR) is the ratio of the total floor area of all buildings on a lot to the area of the lot itself. FAR considers the area of all stories, while Lot Coverage only considers the ground footprint.
