This is where I keep the outside resources worth using when you are working out whether you can buy a place, and what it costs once you do. Everything below is either a primary source I cite on this site (federal housing data, loan rules, tax guidance) or a tool I have used myself. Nothing on this page is a paid placement, and affiliate links are labeled where they appear.
Official data and loan rules
Primary sources. When a number on this site comes from one of these, it is cited on the page it appears.
FHA Handbook 4000.1
The single rulebook for FHA lending, including the 3.5% down rule on 2-to-4 unit owner-occupied property and the self-sufficiency test that applies to triplexes and fourplexes.
FHA loan limits lookup
County-by-county FHA limits, with separate figures for 1, 2, 3 and 4-unit properties. The multi-unit limits are much higher than most first-time buyers expect.
Primary Mortgage Market Survey
The weekly 30-year and 15-year average mortgage rate, published Thursdays. This is the rate every calculator on this site defaults to.
HomeReady
The low-down-payment conventional program with income caps at 80% of area median: 3% down on a one-unit home, 5% down on a two-to-four unit. Worth comparing against FHA before assuming FHA is the cheaper route.[S2]
Housing Vacancies and Homeownership
Quarterly rental vacancy and homeownership rates. Useful for sanity-checking whether a market is actually as tight as the local coverage says.
State of the Nation’s Housing 2026
The annual affordability and cost-burden report, with free data tables. This is where the renter cost-burden figures on this site come from.
Profile of Home Buyers and Sellers
Annual survey of who actually bought and sold. The free highlights carry the first-time buyer share and median buyer age. The full report is member-only.
Publication 527
How rental income, expenses and depreciation work when part of your property is rented and part is your home. Directly relevant if you house hack.
Homebuyer help and down payment assistance
Free or low-cost help that exists whether or not anybody tells you about it.
Buying a house: tools and resources
Stage-by-stage guidance with a rate-comparison tool and plain-language walkthroughs of the documents you will be asked to sign.
Closing Disclosure explainer
An interactive sample closing disclosure. Click any line and it tells you what it is. Read this before your three-day review window, not during it.
Find a housing counselor
Search HUD-approved counseling agencies by ZIP. The counseling is free or low-cost, and for some assistance programs it is required anyway.
Down Payment Resource
Matches you against down payment assistance programs by location, income and household size. Note this is a private company, not a government service, and it asks for your name and email before showing results.
Down payment assistance on a 2-4 unit: the 83-metro survey
I checked 83 metros for whether an owner-occupant can use down payment assistance to buy a two-to-four unit home and live in one unit, and wrote to the agencies where the program materials did not say. A program was found in 73 metros, none in 7, and 3 could not be confirmed either way.[S1] Free to download and reuse under CC BY 4.0: CSV or JSON.
All the data, in one place
Every dataset I publish is listed on one page with its license, its permanent DOI, and a suggested citation: the open data page. Free to download, free to reuse with attribution.
Outside tools for landlords and first-time buyers
A short list on purpose, and it stays short. Some of these I use myself. Others are paid options I think are worth the money for one specific job, and I say which job. Where a link earns me a commission it is labelled as one, and the terms are on the disclosure page.
Camp FIRE Finance
A long-running roundup of financial independence writing and calculators. Good for finding the corner of the FIRE world that matches how you actually think about money.
RentCast
Rent estimates and comps for a specific address. A solid paid option for when the free rent-comp worksheet on this site is not enough and the number has to hold up to someone else. I do not subscribe myself, so treat this as a recommendation and not a review. If you subscribe through this link I earn a commission at no extra cost to you. See the disclosure page.
Baselane
Banking built for landlords: a separate account for the property, rent collection, and expense tagging that keeps rental money out of your personal checking. A solid option for the first months after closing, when the other unit’s rent starts arriving and needs somewhere of its own to land.
I run my own numbers in spreadsheets, so treat this as a recommendation and not a review. If you open an account through this link I earn a commission at no extra cost to you.
Innago
Landlord software for small portfolios: online rent collection, tenant applications and screening, e-signed leases, and maintenance requests in one place. Free on the landlord side, which matters when you own one building and the margin is thin. If you open an account through this link I earn a commission at no extra cost to you.
Start with the free tools here first
Before you go anywhere else, most of what you need is on this site and costs nothing.
All free calculators
Mortgage, house hacking, affordability, DTI, cash-on-cash, cap rate, BRRRR, rent comps and more. No signup, no email wall.
Housing statistics
The data page: first-time buyer share, cost-burdened renters, current rates, and original metro-level numbers on what house hacking a duplex saves.
Duplex market reports
Eleven metros ranked on entry price, monthly cash against renting and long-run durability, with a full report page for each one.
What is house hacking
The starting point if the whole idea is new to you, and the hub for everything else written about it here.
How this page works. Nobody pays to be listed here. I do not sell links, and I do not accept payment for a mention. The links on this page that earn me anything are RentCast, Baselane and Innago, each labeled above and covered on the disclosure page. Government and research sources are listed because I cite them, not because of any relationship. If a tool stops being something I would use, it comes off the page.
Sources: U.S. Department of Housing and Urban Development, Single Family Housing Policy Handbook 4000.1; HUD FHA Mortgage Limits database; Freddie Mac Primary Mortgage Market Survey; Fannie Mae HomeReady product guidance; U.S. Census Bureau Housing Vacancies and Homeownership (CPS/HVS); Harvard Joint Center for Housing Studies, The State of the Nation’s Housing 2026; National Association of Realtors, Profile of Home Buyers and Sellers; Internal Revenue Service Publication 527; Consumer Financial Protection Bureau homebuying resources. Links checked July 27, 2026.
Writing about housing and need a figure? The charts on this site, including diagrams of the 2026 ROAD to Housing Act, are free to republish with attribution. Copy-paste embed code is on the charts page.
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Sources
- [S1] Van to Vault, read 24 September 2026: “status column: program_found x72, none_found x7, unconfirmed x4” vantovault.com.
- [S2] Fannie Mae Eligibility Matrix (owner-occupied 2–4 units, 95% LTV), read 24 September 2026. singlefamily.fanniemae.com.