The Chicago two-flat was built for one deal: the owner lives on one floor and the rent from the other carries the mortgage. Put in a price and a rent and see what living there costs you each month, what it takes to close, and how the numbers look if you move out and rent both. Below the numbers, the building itself, traced room by room, with why each room sits where it does.
A real Chicago two-flat, traced from its plans: two near-identical flats stacked over a full basement. Pick the floor you would live on, then tap any room.
Every field starts at a typical Chicago figure for a two-flat. Change any of them; the listing’s tax bill and a real insurance quote beat our starting points.
Estimates, not a loan offer: mortgage insurance and taxes here are close approximations, and a lender’s quote is the real number. This page is general information, not financial or legal advice.
Every classic Chicago two-flat runs on nearly the same plan, and almost every choice in it traces back to the city itself: its lots, its alleys, its fire, its sewers and its building code.
James Thompson’s 1830 plat of Chicago set streets 66 feet wide, one surveyor’s chain, with a 16-foot alley through each block. The standard lot that grew from it is about 25 by 125 feet, so a two-flat is about 24 feet wide and runs deep: parlor at the street, kitchen at the alley, rooms lined up between.
Most two-flats went up between 1900 and 1920, and a 2014 count found more than 76,000 two-unit buildings in Chicago. The owner lived on one floor and the rent from the other carried the mortgage. The floors are near twins, so the pipes, chimneys and stairs line up, and builders worked from plan books and repeated the same plan down the block.
With the neighbors a few feet away across the gangway, the street and the yard are the only sides with open light. The parlor takes the street and pushes its bay out to catch the sun from three directions; the dining room in the middle borrows light through a wide opening to the parlor.
The alley was the service lane: coal, deliveries and trash came to the rear of the lot, so the kitchen sits there with its own door to the back porch. Chicago still has more than 1,900 miles of alleys, which is why the garbage carts are out back and the front stays for company.
By 1906 the city required two- and three-flats to have a front stair and a back stair, after the 1871 fire and the Iroquois Theater fire. Builders hung the back one outside in wood, because Chicago was the lumber hub and an outdoor stair kept the inside rentable. A 2003 porch collapse that killed 13 people tightened the rules for them again.
Chicago’s ground level was itself rebuilt: from 1855 the city raised its streets 4 to 14 feet to lay its first sewers, and older houses were left below the new grade. Two-flats came later and stand a half story up, first floors 3 to 6 feet above the ground with half windows high in the basement walls that let in daylight and air, which leaves the basement tall enough to finish. Still check it for water: those walls are about a century old.
The bath is tucked against the kitchen so the two share one plumbing wall, in the same spot on both floors, so one stack of pipes serves the building. When these went up, indoor plumbing was still new in many Chicago homes (most working-class homes had it by the 1920s), and one small bath per flat was the standard.
After the 1871 fire the city spread its fire limits, and inside them new wood frame buildings were not allowed. Two-flats wear pressed brick or limestone on the street face and plain common brick down the sides. About 30,000 greystones, fronted in Bedford limestone from southern Indiana, still stand.
A second plan, one flat of about 1,130 square feet from a different building, with angled bays at the front corners. The same order holds: the parlor at the street, the bedrooms down one side, the bath and kitchen at the back. Tap a room.
If you will live in one unit, an FHA loan needs 3.5% down and a conventional loan can go as low as 5% on an owner-occupied two- to four-unit building. For 2026 the FHA limit on a two-unit building in Cook County is $693,050 and the conventional limit is $1,066,250. If you will not live there, expect about 25% down. Add closing costs of roughly 2 to 5% of the price; our closing costs guide has the details, and the financing guide walks the programs.
Yes. Lenders generally count 75% of the other unit’s rent as income when you live in the building, using the lease if it is rented or an appraiser’s market rent if it is vacant. The calculator shows that figure under the 75% tile. FHA asks you to move in within 60 days of closing and live there as your main home.
Property taxes (Chicago homeowners paid about 1.5% of a home’s value in 2022, by the Civic Federation’s count, and bills have risen since in much of the city, so the calculator starts at 1.8% until you type the real bill), insurance, water and sewer, mortgage insurance on a low down payment, repairs on a building that is usually about a century old, and the months a unit sits empty.
It depends on whether you want a tenant. The rent offsets your payment and the second flat can house family later, in exchange for having a tenant down the hall and keeping up an old masonry building. Our two-flat guide covers the history and what to inspect, and the rent vs. buy calculator compares owning against renting over the years you would stay.
The plans are traced from listing floor plans; the room sizes are theirs and are approximate.
We show these buildings every week, and we keep the lenders, inspectors and masons who know them. Bring your numbers.
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