The Floor Space Ratio Calculator helps developers, architects, planners, and property owners determine how much building area can be constructed on a given plot of land. The Floor Space Ratio (FSR), also called Floor Area Ratio (FAR) in some regions, is a crucial planning metric used by local authorities to regulate building density, preserve open space, and ensure efficient urban infrastructure.
By calculating the ratio between the total floor area of all buildings and the site area, users can assess whether a proposed project meets zoning requirements. This calculator is essential for building permit approvals, redevelopment planning, and maximizing the value of real estate within legal limits.
This tool belongs to the urban planning and land development calculator category and supports compliant and sustainable construction planning.
formula of Floor Space Ratio Calculator
Floor Space Ratio (FSR) = Total Floor Area / Site Area
Where:
Total Floor Area = The combined gross floor area of all levels of all structures on the property (in square meters or square feet)
Site Area = The total plot or land area on which the building stands (in the same unit as the floor area)
Example if multi-story:
If a 2-story building has 2 floors of 1,500 ft² each and the site area is 3,000 ft²:
FSR = (1,500 + 1,500) / 3,000 = 3,000 / 3,000 = 1.0
This means the built-up area is equal to the site area, which is typical in moderate-density zoning.
Helpful Reference Table: Typical FSR Limits and Zoning Guidelines
Use this table to understand general zoning categories and what FSR values are typically allowed. Always refer to your local building codes for exact limits.
| Zoning Type | Typical FSR | Description | Development Potential |
|---|---|---|---|
| Low-Density Residential | 0.5 – 1.0 | Single-family homes, suburban housing | Limited floor area |
| Medium-Density | 1.0 – 2.0 | Duplexes, small apartment buildings | Moderate building mass |
| High-Density Residential | 2.0 – 3.0 | High-rise apartments | Vertical expansion allowed |
| Commercial Core | 3.0 – 5.0 | Offices, malls, business towers | Maximized site use |
| Transit-Oriented Zones | Up to 6.0 | Near major transit hubs | Encouraged high-rise, mixed-use |
These numbers help visualize how zoning affects the allowable construction size on different types of land parcels.
Example of Floor Space Ratio Calculator
Let’s calculate the FSR for a commercial plot.
Given:
- Total built-up floor area = 9,000 ft²
- Site area = 3,000 ft²
Step 1: Apply the formula
FSR = Total Floor Area / Site Area
FSR = 9,000 / 3,000 = 3.0
So, the floor space ratio is 3.0, which may be appropriate for commercial or mixed-use zones in urban areas. If your zoning regulation allows up to 3.0 FSR, the design meets the code. If the local maximum is lower, adjustments would be needed to comply.
Most Common FAQs
The ideal FSR depends on your zoning category. Residential zones may allow up to 1.5, while commercial or high-rise areas can go as high as 5.0 or more. Always check with local planning authorities.
If your calculated FSR exceeds zoning limits, your project may be denied approval unless you apply for a special exemption or reduce the built-up area. Some areas allow additional FSR for specific use cases like affordable housing.
Yes. FSR (Floor Space Ratio) and FAR (Floor Area Ratio) are different terms for the same concept. Both express the ratio of total building floor area to land area.