Mark Allen Lakins
austin · current code · september 2026

how many homes fit on this lot now

austin's home amendments changed what a single-family lot can hold. type in the lot; this page reads the caps back for one, two and three units and draws them on the same lot.

inputs

street frontage
front to rear
or type it - depth follows
sf-1 base is 35% / 40% for a single unit; two and three units are 40% / 45% in all three
optional - preservation bonus
verified for sf-3
each side - assumption
assumption
most central austin sf lots

the same lot, three ways

one unit

the house-and-lot everyone already knows

two units

a main house and a second one, or a duplex

three units

the most home allows on one sf lot

what the lot allows

capone unittwo unitsthree units

code checks - the numbers behind the claims

read this before using any of it

what home changed. before february 2024 most single-family lots in austin were allowed one house, and in many districts a small second unit with strings attached. phase 1 of the home amendments allows up to three units on sf-1, sf-2 and sf-3 lots of at least 5,750 sf, with building coverage capped at 40 percent and impervious cover at 45 percent, and a floor-area cap that steps up with the unit count. phase 2 let a single home be built on a lot as small as 1,800 sf, which is what makes the subdivision of an ordinary lot into two or three sellable pieces possible at all. every lot in these districts changed what it can hold, and most owners have not looked.

the numbers are the caps, not the design. the floor area on the cards is the most the code lets you build, before the setbacks, trees, drainage, the shape of the lot and the budget have said anything. a real project lands under these figures, sometimes well under. the drawings above are footprint blocks scaled to the coverage cap, not floor plans. use the page to know what the lot is worth talking about, then get someone to draw it.

what actually stops a project is usually not zoning. it is a utility threshold you find out about after paying for design, a subdivision process sized for a different kind of project, and a review framework still catching up with the programs the city created. that is its own field note, and the utility side has its own tool: run that one before assuming the three-unit number here is the number.