FAR (Floor Area Ratio)
The ratio of total building floor area to lot size — caps how much you can build.
Floor Area Ratio is calculated as total enclosed floor area divided by lot size. A FAR of 0.5 on a 6,000 sqft lot means you can build up to 3,000 sqft of enclosed floor area total (across all structures).
In the City of LA, R1 zones typically have a 0.45–0.6 FAR cap. ADUs receive a partial FAR exemption — the first 800 sqft of an ADU does not count against your FAR limit. This is what makes adding an ADU possible on lots that are already at maximum FAR.
Related terms
- ADU (Accessory Dwelling Unit)A self-contained second home on a residential lot, with its own kitchen, bath, and entrance.
- SetbackMinimum distance a structure must be from a property line.
- BMO (Baseline Mansionization Ordinance)City of LA rules limiting the size of single-family homes in non-hillside R1 zones.
People also ask
FAQ — FAR (Floor Area Ratio)
What does "FAR (Floor Area Ratio)" mean in plain English?
The ratio of total building floor area to lot size — caps how much you can build.
Why does FAR (Floor Area Ratio) matter for a California ADU or remodel?
FAR (Floor Area Ratio) comes up in the zoning and land-use side of nearly every Greater LA and Bay Area project we touch. Floor Area Ratio is calculated as total enclosed floor area divided by lot size. Getting it right at design saves rework later — getting it wrong is one of the most common reasons permits stall.
Where will I see FAR (Floor Area Ratio) on my own project?
Most owners run into FAR (Floor Area Ratio) during the design or plan-check phase. Your project manager flags it on the schedule, walks you through what the city expects, and confirms documentation is in place before the inspection that depends on it.
Does FAR (Floor Area Ratio) cost extra?
Sometimes — depends on whether it adds scope (a report, a structural detail, a fee) or just a paperwork step. Anything cost-impacting is itemized in your contract or change order, never buried in the invoice.
Who at Alpha Dream handles FAR (Floor Area Ratio)?
The project architect owns design-level decisions; the permit runner owns city interactions; the project manager owns field execution. You always know who to ask.