tools

Small working calculators that draw the answer. Every default is an assumption, every rule is cited on the page, and none of it is advice. Where a field note is about one of these, it links back here.

Built in Austin, Texas, for Austin, Texas. Every code citation on these pages - a zoning cap, a parking rule, a plumbing table - is Austin's, or Texas's for the state-law ones, and does not apply anywhere else. The underlying math (yield on cost, fixture counts, floor area) is ordinary arithmetic and works in any market once you swap in your own numbers; the rule-based check cards do not travel with it. Reading this from outside Central Texas, treat every code card as an example of the kind of threshold that exists, not a rule that applies to you, and find your own city's and utility's equivalent before relying on anything here. Read the full disclaimer before using any of them.