What is Floor Area Ratio (FAR)?

Scott McCallum, Jeff Allen | April 2025

FAR is a measure of urban built density, measured as a building's total floor area relative to the size of its lot. It is calculated as:

$\mathrm{FAR}=\frac{\mathrm{Total\; Building\; Floor\; Area}}{\mathrm{Lot\; Area}}$

Higher FAR values indicate denser development, while lower values suggest less built-up land use.

A tall, narrow tower and a low, sprawling building can have the same FAR if their total floor areas are equal. Design choices like setbacks, height limits, and lot coverage can influence massing while maintaining the same FAR:

FAR: 1.0 FAR: 1.0 FAR: 1.0

Methodology

This visualization was created combining 3D massing and property boundary data from the City of Toronto’s Open Data Portal. For the FAR calculations, we assumed an average building floor height of 3 meters.

Data download links

• FAR Data
• 3D Massing
• Property Boundaries

Explore the project on GitHub.

Map attributions:
OpenStreetMap,
City of Toronto