AMI is the key number behind affordable housing eligibility. Learn how it's calculated and what it means for your housing search.
If you've looked into affordable housing at all, you've seen the term AMI. It shows up everywhere—"units restricted to 80% AMI," "income limit at 60% AMI"—but it's rarely explained. Here's what it means and why it's the most important number in your housing search.
What AMI stands for
AMI stands for Area Median Income. It's the midpoint income for a given metro area—meaning half of all households earn above it, and half earn below. HUD calculates AMI annually for every metro area in the country, adjusted for household size.
What it looks like in King County
For 2026, the estimated AMI for a four-person household in King County is approximately $135,000. That number shifts for smaller and larger households:
1 person
~$94,500
2 people
~$108,000
3 people
~$121,500
4 people
~$135,000
How affordable housing programs use AMI
Programs set income limits as a percentage of AMI:
50% AMI: Targets very low-income households. Common in deep-subsidy LIHTC and public housing.
60% AMI: Standard threshold for most LIHTC developments.
80% AMI: The most common threshold for MFTE units in Seattle and the Eastside. This is where most moderate-income renters become eligible.
100% AMI: Some newer MFTE and MHA programs extend eligibility here.
Why it matters for your search
Every income-restricted listing has an AMI cap. Knowing your household's income as a percentage of AMI tells you instantly which programs you're eligible for—and which ones to skip. It turns a confusing search into a targeted one.
Roost surfaces AMI thresholds clearly on every listing so you can filter by what actually applies to your household.