What Is a Studio Apartment? Definition, Sizes and How It Compares to a One-Bedroom

The cleanest studio apartment definition comes from the International Building Code, the model code most U.S. cities adopt for apartment buildings, often with local amendments. The City of Portland's building official determination on minimum dwelling unit size summarizes it: any dwelling unit that has living, sleeping, cooking and eating provisions in one room is, by definition, an efficiency dwelling unit.

The 2021 edition of the code, section 1208.4, sets the main room of an efficiency unit at no less than 190 square feet, down from 220 square feet in earlier editions. It also requires a separate closet, kitchen facilities with working clearances, and a separate bathroom with a toilet, sink and tub or shower. A studio is a complete home in one room. A room with shared bathrooms down the hall is something else, usually a single-room occupancy unit or a rooming house.

Three practical consequences of that definition:

• The bathroom is always separate. If the toilet is in the main room behind a curtain, walk away.
• The kitchen can be anything from a full galley to a kitchenette. Some studios put the kitchen in a separate small room, which still counts as a studio because no bedroom exists.
• The code sets a floor, and cities can set their own. Your city may have adopted a different edition or amended the minimum, so check the local building department if size matters to a decision.

What is a studio flat?

Same thing, British English. In the UK and much of the Commonwealth, an apartment is a "flat," so a studio apartment becomes a "studio flat." Canadians often say "bachelor" or "bachelor apartment" for the same layout. In some U.S. markets, especially older buildings, "efficiency" is the more common listing word.

These labels describe layouts, and brokers use them inconsistently. A New York brokerage glossary from Nest Seekers International gives definitions that match common usage: a studio is one or two rooms with a combined living and sleeping area; an alcove studio has a separate alcove, often L-shaped, that can be used as a sleeping area; and a junior one-bedroom or convertible has an alcove off the living room that can be converted into a bedroom or used for dining.

The important column is the last one. Legally, a junior one-bedroom is still a studio; the better floor plan does not add a bedroom. That matters for the rent you should pay, and it can matter for occupancy limits, roommate arrangements and resale if you ever buy a condo unit with this layout. If you are weighing a studio inside a condo building against one in a rental community, our comparison of condominium vs apartment rentals covers how ownership changes the rules you live under.

A temporary partition to carve a bedroom out of an alcove is common in dense markets. Before you install one, read the lease and the building's alteration rules and get any approval in writing. A partition that blocks a window or a sprinkler head can also turn a layout fix into a fire safety problem.

This is where "studio vs 1 bedroom apartment" stops being a matter of taste. Building and housing codes, not listings, decide what qualifies as a sleeping room, and the rules vary by the code your city adopted.

For houses and other buildings under the International Residential Code, the Minnesota Department of Labor and Industry's fact sheet on emergency escape and rescue openings, based on the 2018 IRC as adopted in Minnesota, states that every sleeping room needs at least one operable emergency escape and rescue opening. The opening must have a net clear area of at least 5.7 square feet (5 square feet at grade), a clear height of at least 24 inches, a clear width of at least 20 inches, and a sill no more than 44 inches above the floor. Portland's determination adds that a habitable room other than the main room, such as a sleeping room, may be as small as 70 square feet.

Apartment buildings are generally regulated under the building code rather than the residential code, and cities add their own housing codes on top, so the exact window, light and size rules for a bedroom can differ from the house rules above. The practical test for a renter is simpler: if the "bedroom" has no window you could climb out of, ask the landlord in writing whether the space is approved as a bedroom. If the answer is vague, price the unit as a studio.

The most current national snapshot comes from RentCafe's August 2026 analysis of Yardi Matrix data covering buildings with 50 or more units in the 100 U.S. cities with the largest apartment stock. Studios averaged 460 square feet, after gaining six square feet over the prior year. One-bedrooms averaged 735 square feet and two-bedrooms 1,095 square feet, with the overall average across unit types at 910 square feet.

Those are averages from large professionally managed buildings. Older walk-ups, converted houses and micro-unit projects can be much smaller, and the same report found apartments in general are smallest in Seattle and Portland and largest in Tallahassee. A studio near the code minimum of a 190-square-foot main room and a 550-square-foot studio in a newer suburban complex are both called studios.

Listing square footage is also measured inconsistently. Some landlords measure to the outside of walls, some include balconies or closets, some round generously. Ask for a floor plan with dimensions, or measure during the tour. Two numbers tell you more than the total: the length of the longest wall without a window, door or radiator, and the depth of the space where the bed will go. Our guide on how to furnish a studio apartment shows how to turn those measurements into a working layout.

Studios usually rent for less in total than one-bedrooms in the same building. HUD builds that relationship into its Fair Market Rents, which are used for the Housing Choice Voucher program. In its FY 2026 Fair Market Rents notice, HUD explains that it estimates two-bedroom rents first and then applies bedroom ratios for each area. Efficiency units are constrained to fall between approximately 0.69 and 0.87 of the two-bedroom figure, and one-bedrooms between 0.76 and 0.91.

That gives you a sense of scale, but your decision happens at the building level. Run three comparisons:

1. Monthly rent gap. The total difference you would pay each month and over the lease.
2. Price per square foot. Divide rent by usable square footage. Say a 460-square-foot studio rents for $1,600 and a 735-square-foot one-bedroom for $1,950. The studio costs about $3.48 per square foot and the one-bedroom about $2.65. The studio is cheaper per month and more expensive per foot.
3. Cost of the extra room elsewhere. If the one-bedroom lets you skip a coworking membership or a storage unit, subtract that from the gap.

Then add the costs that scale with size: utilities, renters insurance contents limits, furniture and moving. Smaller homes typically mean smaller bills on all four. Our breakdown of how much it costs to move a studio apartment covers the last one.

A studio works best when the apartment is mostly a place to sleep, cook and recharge, and the city is where life happens. People who pick studios happily tend to share a few traits: they live alone, they own little furniture, they value location over space, and they are in a transition such as a new job, a first year in a city or a move before buying.

It gets harder when your home has to do several jobs at once. Daily video calls with your bed in the frame, a partner on a different sleep schedule, a hobby that needs a dedicated table, or a large dog all push toward a one-bedroom or a junior one with a real partition.

Studio apartment pros

• Lower monthly rent than a one-bedroom in the same building, in most markets.
• Lower utility bills and less to clean.
• Access to neighborhoods or buildings that would be out of reach with a larger unit.
• Less furniture to buy and a cheaper, faster move.

Studio apartment cons

• No acoustic or visual separation between sleeping and everything else.
• Cooking smells reach your bedding and clothes.
• Guests stay in your bedroom by default.
• Storage runs out quickly, and the bed dictates the whole layout.

Start by deciding how long you expect to stay. A studio that feels clever for nine months can feel tight at month twenty. If you are unsure, compare the shortest lease available with a standard twelve-month term; the trade-offs are laid out in our guide to fixed-term leases vs month-to-month rentals.

If you are signing from another city, a studio is the unit where a few feet of misjudged space hurts most. Ask for a dimensioned floor plan and a live video walk-through with a tape measure in frame. Our guide to renting an apartment out of state covers how to verify the listing and avoid scams.

Then compare studios and one-bedrooms in the same neighborhoods on Leevli's rentals, and ask people who live in the building what the layout is like after a year on Ask a Resident.

Floor plans show square footage; only someone living in the same layout can tell you how the space behaves day to day.

• Does your studio have the same floor plan as this one, and where did you end up putting the bed?
• How much does cooking smell travel through the room, and does the range hood vent outside or recirculate?
• How much noise comes through the walls and the entry door at night?
• Did management let you install a partition or room divider, and what did they require?
• Is there storage anywhere in the building, and is there a waiting list?
• Do studio residents here tend to renew or move out after the first lease?
• If you moved from a studio to a one-bedroom in this building, was the rent difference worth it?