Yes In My Spare Room (YIMSR)

America may already have millions of possible housing units hiding in spare rooms.

This tool estimates how much shared-housing capacity may already exist inside occupied homes.

Start here

New here? Try and see the estimate appear below.

How to use it

Search a ZIP, state, United States, City, ST, City ST, County, ST, or County ST.

Try these

Search an area to estimate occupied-bedroom surplus or shortage.

Why YIMSR

The core idea

America can increase housing capacity not only by building more homes, but also by making better use of spare bedrooms that already exist inside occupied homes.

What This Measures

Possible capacity, not proof of vacancy

A spare bedroom here means possible capacity inside occupied homes. It does not mean the room is literally empty today, and it excludes vacant and seasonal homes entirely.

FAQ

Common Questions

Does this count vacant homes or vacation homes?

No. This tool focuses on occupied homes. It is not trying to measure vacant houses, seasonal homes, or second homes. It is asking a narrower question: how much housing capacity may already exist inside homes that people already live in. FYI: very roughly, there are about 13 million spare rooms in vacation homes and around 25 million spare rooms in homes that are currently vacant.

Does a “spare bedroom” mean the room is empty?

Not necessarily. A spare bedroom here means possible capacity, not proof that a room is sitting unused. Some of these rooms are offices, nurseries, guest rooms, hobby rooms, or storage spaces. The point is not to claim that every room is available tomorrow. It is to show how much room there may be for flexibility.

Is this anti-YIMBY or anti-construction?

No. I agree with a lot of the YIMBY case for building more housing, and in many places we clearly need more construction. YIMSR is not meant to replace that argument. It is meant to widen it by asking whether the housing conversation should also pay more attention to the bedrooms that already exist inside occupied homes.

Is this legal?

It depends. Co-living, boarding, and other shared housing arrangements used to be very common in American life, but many places now restrict them through occupancy limits, zoning rules, leases, or HOA policies. If your area makes simple shared housing unnecessarily difficult, one constructive response is to encourage local and state leaders to make these arrangements easier and more workable.

How can a community increase its spare room capacity?

Some of it comes from household choices, and some of it comes from the built environment. Families may decide that siblings can share a room. Homeowners may convert underused attics, basements, offices, or dens into legal bedrooms. Builders and renovators can design homes with future boarders, relatives, or roommates in mind. And local governments can help by allowing more flexible shared housing arrangements.

How exact are these numbers?

They are estimates, not a literal room-by-room census. The tool uses recent Census survey data on occupied bedrooms, household structure, and children, then applies transparent assumptions to produce an estimate. The goal is to be grounded and useful without pretending to know more than the data can really tell us.

How do I host people in my spare room?

You can of course invite a friend or family member to live in your spare room. Alternatively, you may consider renting it to well-vetted strangers through a platform like PadSplit.

How do I find a spare room to stay in?

Consider reaching out to members of your network to ask if they know a friend or family member who might have a spare room that could be made available. Alternatively, you can look into room rental platforms like PadSplit.

County Map

Where modeled spare-bedroom capacity looks higher or lower

This map colors U.S. counties by estimated spare bedrooms for every 10 occupied households. Click a county to load the full estimate; hover just to browse quickly.

Legend

Loading county map...
Methodology and sources

Where the numbers come from

  • This tool uses recent American Community Survey data from the U.S. Census Bureau.
  • It combines occupied bedroom counts, household size, couple-household counts, and the number of people under 18.
  • The model then estimates how many bedrooms are already spoken for under these assumptions and compares that to occupied bedroom supply.

Technical table details

  • Occupied bedrooms: ACS table B25042
  • Household size: ACS table B11016
  • Total, married-couple, and cohabiting-couple households: ACS profile table DP02
  • People under 18: ACS profile table DP05

When the PUMA follow-up appears

  • The PUMA follow-up uses ACS 2024 1-year PUMS microdata at the PUMA level.
  • PUMAs are broader regions than ZIP codes, cities, or many counties, so this section is more regional and inferential than the main estimate.
  • For some counties and states, the site uses precomputed countywide or statewide aggregates built from one or more PUMAs.
  • For many ZIP searches, the site now pairs the ZIP with a best-fit broader county/PUMA pattern rather than a ZIP-specific microdata profile.

Source data used for this estimate

    Keep Going

    If this argument resonates, take the next step.

    YIMSR is both a measurement exercise and an invitation: to see spare rooms as real housing possibility, to consider shared housing where it makes sense, and to widen the conversation beyond construction alone.

    Read The YIMSR Blog

    Share this tool, test your own county or ZIP code, and read more at yimsr.substack.com.

    About Andrew

    Who built this

    Andrew Berg

    Andrew Berg graduated from Franklin & Marshall College in 2012 with a double major in history and government.

    After graduating, he taught middle school science in Baltimore through Teach for America, while earning a Masters of Education from Johns Hopkins University.

    He now serves as Area Director for InterVarsity Christian Fellowship in central Pennsylvania, supervising staff, volunteers, and student leaders at fifteen colleges.

    Since 2012, Andrew has practiced co-living in a variety of forms. Whether through short-term visits or long-term guests, he has experienced the highs and lows of shared housing and still loves it.

    If you want more on the argument behind YIMSR, or on Andrew's own experience with shared housing, visit the YIMSR blog.

    Questions, feedback, or media inquiries? Reach me through the YIMSR blog.