The best barndominium size for most families is a 40-by-60-foot footprint, about 2,400 square feet, which fits three bedrooms, two baths, an open living area, and a shop bay under one roof without paying for steel you will not use. Smaller couples and downsizers do well in a 30-by-40 or 40-by-40, while a home plus a large workshop or a second story points you toward 40-by-80 or wider. There is no single right size; the best one is the smallest footprint that holds your rooms, your shop, and the way you live day to day.
This page sits under the metal building homes pillar and answers the size question on its own terms: how to size a barndominium from the inside out, what the common footprints give you, and where width, length, and ceiling height earn their cost. If you have seen owners argue over 40-by-60 versus 40-by-80, this is the framework that settles it for your build, not theirs.
The method
How to choose the right barndominium size
Size the building from the inside out, not the outside in. Start with the rooms you need, add the shop or garage space you want under the same roof, then let those square feet set the footprint. A barndominium frames a wide, column-free span, so you can place interior walls almost anywhere, which is why the floor plan should drive the size rather than the other way around. Pick the steel first and you end up padding rooms to fill it, or cramming a layout that never sat right.
Three numbers do most of the work: width, length, and clear height. Width sets how deep your rooms can run and whether an open great room feels generous or tight; barndominiums commonly run 40 feet wide because it splits cleanly into a living side and a shop side. Length is the cheapest square footage you will ever add, since stretching the building costs less per foot than widening it. Height decides whether you get a loft, a second floor, or tall RV and equipment doors in the shop bay.
Build for the life, not the listing
The most common sizing mistake is buying square footage to match a neighbor’s build or a photo online. Walk your own days instead: how many bedrooms you sleep, whether you cook and gather in one room, what you park or store, and whether a shop sits under the roof or stands separate. The right size falls out of those answers, and the best sizes for a barndominium guide turns each one into a footprint.
By footprint
Common barndominium sizes and what each one fits
The footprints below cover what most barndominium buyers land on, from a compact one-story to a home-plus-shop layout. Read them as living space, since a barndominium with a workshop under the same roof needs a bigger footprint than the home alone would suggest. Square footage here is the full shell; carve out the shop bay and the living area is smaller.
| Size | Footprint | Best for |
|---|---|---|
| 30×40 | 1,200 sq ft | Couples, downsizers, a tight 2-bed with no shop |
| 40×40 | 1,600 sq ft | Small family, 2–3 bed, modest attached bay |
| 40×60 | 2,400 sq ft | The common sweet spot: 3 bed, 2 bath, plus a shop |
| 40×80 | 3,200 sq ft | Home plus a full workshop or garage under one roof |
| 50×100 | 5,000 sq ft | Large family, multi-use, or a big working shop |
Full-shell footprints. A shop bay under the same roof shrinks the living area, so size up if you want both.
Why does 40-by-60 keep winning? It clears enough width for a real open-concept living side and still leaves a two or three-bay shop, all on a frame size that prices efficiently. Go smaller and the shop is the first thing to disappear; go bigger and you are paying for floor you may furnish slowly. If you want the home and a serious workshop, jump to 40-by-80 rather than squeezing both into 40-by-60. The living-quarters kit format is built for exactly that home-and-shop split.
The tradeoffs
Where width, length, and height change the answer
Two builds with the same square footage can live nothing alike, because how you reach the number matters as much as the number itself. Length is the cheap dimension, so when you want more space on a budget, add feet to the length before you widen the frame. Width is the expensive one, but it buys the open-span feel that makes a barndominium worth building, so do not starve it to save.
Height and stories reshape the whole question. A taller eave lets you finish a loft over part of the living area, and a true second story can double your living space without growing the footprint, which is the move when your lot is small or your view is up. Our two-story metal home guide walks where a second floor pays off and where a single, longer story is simpler and cheaper to build.
Size the barndominium to the smallest footprint that holds your rooms and your shop. Empty square footage costs the same to frame, insulate, heat, and cool as the rooms you put to use.
The cost link
How size drives the budget
Size is the single biggest lever on what a barndominium costs, because you buy the shell by the pound and you finish, insulate, and condition every square foot you build. Doubling the footprint does not double the bill, since the price per square foot falls as fixed costs spread over more floor, but a bigger building still costs more to put up and far more to finish. The shell is the cheap part; the interior build-out is where most of the budget goes, and it scales straight with floor area.
That link cuts both ways when you pick a size. Round up and every extra foot adds steel, foundation, drywall, flooring, and heating load for the life of the building. Round down too far and you box yourself into a layout that fights how you live. The honest target is the smallest footprint that fits the floor plan you will keep. When you have a number, price it against the metal home versus a traditional house math so you know what the size buys you against a stick-built home of the same area.
Related
Read more
Sizing a barndominium connects to floor plans, cost, and the home vs house decision. Follow these next:
- Metal building homes: the complete guide (the parent pillar).
- Best sizes for a barndominium (the size guide this answer expands on).
- Barndominium floor plans and layouts (turn a footprint into rooms).
- Cost to build a barndominium from a kit (how size moves the budget).
- Two-story metal building homes (more space without more footprint).
