NYC ADU Permit Fee Calculator
Estimate the New York City Department of Buildings permit fees for an Accessory Dwelling Unit under City of Yes. Powered by the DOB work-permit fee schedule, with each line item linked to the underlying NYC Administrative Code / 1 RCNY §101-03 citation.
Project details
About this calculator
Table 28-112.2 prices the two kinds of ADU on different bases, which is why this calculator asks how yours is being built.
- A detached backyard unit is its own new building, billed on floor area: $0.06 for each square foot or fraction of one, but not less than $130 per structure. Every ADU small enough to be permitted under the zoning (800 sq ft or less) lands on that $130 minimum.
- A unit inside the existing building is an Alteration Type 1, billed on the estimated cost of work (NYC Admin Code §28-112.3): a $170 minimum filing fee covers the first $5,000, then $2.60 for each $1,000 or fraction of one above that. Type 1 is the right row because an ADU always needs a new or amended certificate of occupancy. This calculator derives the estimated cost of work from your square footage using a documented per-sqft basis; DOB uses the cost you file.
Both paths also carry the flat $45 records-management fee for a one-, two- or three-family dwelling (1 RCNY §101-03). Where the job results in a new or amended certificate of occupancy, half the work-permit fee is due with the first application for approval of construction documents and the rest before the permit issues.
City of Yes ADUs
City of Yes for Housing Opportunity (Local Laws 126 & 127, 2024) permits ADUs up to 800 sqft on 1- and 2-family lots citywide, subject to rear-yard, side-yard, historic- district, and flood-zone rules. Use the A-du test-fit tool to check feasibility for a specific lot.
Estimate only
Figures are best-effort estimates for planning. The rates come from Table 28-112.2 as amended by Local Law 77 of 2023 and were checked against it in September 2026, but the statute lets DOB raise them by rule, additional sub-permit, electrical and plumbing fees apply on top, and DOB NOW computes the real figure at filing. Confirm final fees with the NYC Department of Buildings.