Does an in-law suite count as square footage?
Published August 27, 2026
Yes, if it is part of the house. An in-law suite that is attached, above grade, finished, and reached through finished space inside the house counts as gross living area under ANSI Z765, kitchenette and all. A suite in the basement is below-grade area, and a suite in a detached building is a separate structure.
Interior connection is the test
Many in-law suites have their own exterior door, which is fine as long as there is also a door into the house through finished space. If the only access is from outside, ANSI's finished-connection rule treats it like an ADU and it is reported separately.
Second kitchens and zoning
A second kitchen can raise zoning questions (is this a two-unit property?) and permit questions. Those affect value and lending, not the measurement. If the suite was built without a permit, the unpermitted addition rules apply on top.