Architect Tools

Architecture · Calculator

Floor Area Ratio Calculator

Calculate floor area ratio from total gross floor area and site area.

Project inputs

Enter your project values, then press Calculate.

How this calculator works

Calculate floor area ratio from total gross floor area and site area.

FAR = gross floor area ÷ site area

How to use the Floor Area Ratio Calculator

1. Enter project inputs

  • Gross floor area (m²)
  • Site area (m²)

2. Review the results

  • Floor Area Ratio
  • Floor area / site
  • GFA at FAR 1.0

3. Check the calculation

The calculator uses the following core relationship:

FAR = gross floor area ÷ site area

Estimating note: Actual material quantities can vary with site conditions, detailing, product dimensions, installation method, and waste.

Floor Area Ratio Calculator FAQ

What does the Floor Area Ratio Calculator calculate?

Calculate floor area ratio from total gross floor area and site area.

What information do I need to use the Floor Area Ratio Calculator?

The calculator uses inputs such as Gross floor area (m²), and Site area (m²). Use values from your drawings, measurements, product data, or project specifications.

How should I use the results from the Floor Area Ratio Calculator?

Use outputs such as Floor Area Ratio, Floor area / site, and GFA at FAR 1.0 for estimating and cross-checking. Before purchasing or construction, confirm the dimensions, units, waste factors, supplier packaging, and project specifications.