An 18.9-month build is an 18.9-month interest rate bet. That’s the average time from permit authorization to completion for multifamily buildings in 2025, per NAHB’s Na Zhao working from the Census Bureau’s 2025 Survey of Construction. It’s 0.7 months better than 2024 and still nearly seven months worse than the 12.0-month series low set in 2013.
The increase sits in the build, not the entitlement
Start-to-completion rose from 13.4 months in 2009 to 16.5 months in 2025. That matters, because the usual explanation for slower housing delivery is entitlement and permitting. On multifamily, the Census data points at the construction phase itself.
NAHB’s explanation is mix, and its own numbers back it. Buildings with 50 or more units went from 43% of multifamily buildings in 2009 to 57% in 2025. Bigger buildings take longer. Not complicated.
By size in 2025: 20-plus units averaged 21.7 months, against 16.2 in 2015 and 22.1 in 2024. The 10-to-19-unit band came in at 18.5 months versus 14.0 in 2015. Two-to-four-unit buildings ran 14.9 months.
The missing middle got slower while everything else improved
The 5-to-9-unit segment is the outlier, and not in a good way. It averaged 21.5 months in 2025, up from 19.1 in 2024 and up from 13.2 in 2015. Every other size band improved year over year. This one didn’t.
That’s an awkward finding for a policy environment where a dozen states have spent two years rewriting zoning specifically to unlock small-scale multifamily. If the buildings those reforms enable take 21.5 months to deliver and are getting slower, the schedule risk on a small-balance construction loan is worse than the pro forma assumes. The honest caveat: this is the thinnest cell in a sample survey, so treat it as directional rather than settled.
Regional spread is a pro forma difference
Northeast 21.9 months. West 20.6. South 17.5. Midwest 16.6.
A 5.3-month gap between the Northeast and the Midwest, at current construction-loan pricing, is a materially different deal on identical unit counts. It’s also why capital keeps finding the Sun Belt and the Midwest even when rents look better elsewhere.
Two things to discount before you plan around this. First, a 0.7-month improvement on an 18.9-month average sits inside the noise band of a sample survey, and NAHB doesn’t publish confidence intervals here. Second, watch what shortening means in a downturn. Fewer starts chasing the same trades will compress schedules on its own. Some of this improvement is slack in the labor market, not productivity, and it will reverse when starts recover.
Large purpose-built residential still runs long on its own terms. The University of Cincinnati’s 1,300-bed Block 1 and Block 2 complex broke ground in August 2024 for an August 2027 occupancy, three years for four buildings on a single hard deadline.