Building coverage calculator

Calculate lot coverage and verify zoning compliance instantly

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The Building Coverage Calculator helps architects, developers, and planners determine the percentage of a lot covered by building footprint and verify compliance with zoning regulations.

Building coverage, also known as lot coverage or surface area ratio, is a critical zoning metric that controls development density by limiting the amount of impervious surface on a property. This ensures adequate open space for landscaping, drainage, and environmental protection.

Enter your lot area and building footprint to instantly calculate coverage percentage, remaining permeable area, and compliance status against your local zoning maximum. The calculator includes a visual diagram showing the relationship between lot size and building footprint, making it easy to understand coverage implications for your design.

Features

Everything you need

Instant coverage ratio calculation
Zoning compliance verification
Visual lot and building footprint diagram
Permeable area calculation
Adjustable maximum coverage limits
Pass/fail compliance indicator
Imperial and metric unit support

How it works

Simple workflow

1
Enter your total lot area
2
Input the building footprint area
3
Set your local maximum allowed coverage percentage
4
View calculated coverage ratio and compliance status
5
See remaining permeable area for landscaping

Use cases

Built for real-world scenarios

Zoning compliance verification

Quickly verify that proposed building footprints meet local zoning coverage limits before detailed design work.

Site feasibility analysis

Evaluate development potential by calculating maximum allowable building footprint for a given lot.

Design optimization

Adjust building footprint to maximize development while maintaining zoning compliance and permeable area requirements.

Permit applications

Generate accurate coverage calculations for building permit submissions and zoning variance requests.

FAQ

Frequently asked questions

Building coverage (also called lot coverage or surface area ratio) is the percentage of a lot area covered by building footprint. For example, a 5,000 sq ft lot with a 2,500 sq ft building has 50% coverage.

Coverage measures the footprint percentage on a single level, while FAR (Floor Area Ratio) measures total floor area across all levels. A building can have low coverage but high FAR if it has many floors.

Coverage limits vary by zoning district, typically ranging from 30-70% for residential and 60-90% for commercial. Dense urban zones may allow higher coverage, while suburban zones often require more open space.

Coverage typically includes all building footprints, covered parking structures, and other impervious structures. Open decks, patios, and landscaping usually don't count, but local codes vary—always verify with your jurisdiction.

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We're always looking to improve our calculators. If you have ideas for new features, improvements, or found something that could work better, we'd love to hear from you.

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