Guide · Seattle · Updated July 2026

What can you build on a commercial, downtown, or industrial lot?

Housing isn't the only thing Seattle land does. A practical guide to development capacity when the lot isn't residential — and why the headline number changes.

Ask "how many homes can I build here?" on a residential lot and you get a unit count. Ask the same question on a commercial, mixed-use, downtown, or industrial lot and the honest answer is a different number entirely: buildable floor area. On non-residential land, capacity is governed by floor-area ratio (FAR) and height, not a count of dwellings — so the number that matters is square feet, and how you fill them is up to the project.

The one formula behind all of it

For non-residential zones, buildable capacity starts from a simple relationship: FAR × lot area = chargeable floor area. A 12,000-square-foot lot with a FAR of 4.5 permits roughly 54,000 square feet of chargeable building. Height then determines how that floor area stacks. Everything below comes down to which FAR and height apply to the mapped zone — and those are set by specific tables in the code, not rules of thumb.

Neighborhood Commercial & Commercial (SMC 23.47A)

NC1, NC2, NC3, and the C1/C2 commercial zones share one FAR-and-height framework. FAR is set by the mapped height suffix, residential and commercial uses are both allowed, and parking requirements ease near frequent transit. These are the classic mixed-use corners: ground-floor retail with apartments or offices above.

Seattle Mixed (SMC 23.48)

Seattle Mixed zones carry a by-right base FAR, with additional floor area available above that base only through the incentive and affordability provisions of Chapter 23.58A. The base is the number to underwrite; the bonus is upside you have to earn.

Downtown (SMC 23.49)

Downtown is where the spread gets dramatic, because it runs on incentive zoning: a modest by-right base FAR plus bonuses and transfer of development rights up to a much higher maximum, and both figures are specific to the mapped height district. A DOC1 lot, for example, starts at a base FAR of 6 and can reach a maximum of 21 with bonuses — the difference between a mid-rise and a tower. Get the height district wrong and the whole pro forma is wrong.

Industrial & Maritime (SMC 23.50 / 23.50A)

Seattle's industrial land splits into the legacy General Industrial and Industrial Buffer zones (IG1, IG2, IB) and the 2023 Industrial and Maritime zones (MML, II, UI, IC). The legacy zones carry a flat FAR of 2.5 for all uses, with below-grade floors and accessory parking exempt from the calculation. The newer zones set FAR by mapped height, and only Industry & Innovation (II) earns floor area above its base — by providing bona fide industrial space, mass-timber construction, or TDR. Residential is prohibited across industrial land except in Urban Industrial (UI), which allows limited conditional-use housing.

The bottom line

A commercial, downtown, or industrial lot doesn't have a "unit count" — it has a buildable envelope measured in floor area, set by the FAR and height mapped to that exact parcel. The only way to know yours is to run it against the adopted code for its zone.