Shipping Container Home: Dimensions, Plans & Cost

Start with the two footprints. A 20 ft container offers 5.898 × 2.352 m = 13.9 m² (150 ft²) — one room. Realistic single-box programs: a studio (bed + kitchenette + shower room), a home office, or one module of a larger plan. A 40 ft container offers 12.032 × 2.352 m = 28.3 m² (305 ft²) — enough for a genuine one-bedroom layout in a line: bedroom (3.0 m) · bathroom (1.8 m) · kitchen (2.4 m) · living (4.8 m), each zone the full 2.35 m across.

The width rules the plan. After 50–75 mm of insulation and lining per side, the clear interior is 2.15–2.25 m. A standard double bed (1.9 m long) fits across the container with barely 0.3 m to spare, so beds almost always run across the box with a walk-past, or along one wall. A corridor beside a room is impossible in one box: 0.9 m of hallway leaves ~1.3 m of room. Single-box plans are therefore enfilade — you walk through each zone to reach the next, with wet rooms at one end, not the middle.

Wet-zone placement follows the plumbing: put bathroom and kitchen back-to-back at the end nearest the utility connection, so all supply and waste penetrations cluster in one bay of the steel floor. In two-box plans, mirror the wet zones across the joint line and both units share one riser.

The standard answer to the width problem is joining boxes: 2 × 40 ft HC side by side ≈ 56 m² with a 4.7 m wide open plan once the shared walls are cut (a continuous steel beam replaces them); 3 boxes ≈ 84 m²; 4 boxes ≈ 112 m² — a full 3-bedroom footprint. Leaving a 3–4 m gap between two parallel boxes and roofing it over adds a cheap, container-free living room in the middle.

Four proven plan templates cover most builds. Studio (1 × 20 ft, 13.9 m²): wet room at the closed end, kitchen wall, bed/living at the glazed door end. One-bed (1 × 40 ft HC, 28.3 m²): the enfilade described above. Two-bed (2 × 40 ft HC joined, 56 m²): bedrooms and bathrooms in one box, kitchen-living across the opened pair. Three-bed courtyard (3 × 40 ft HC, ~100 m² incl. the roofed gap): two parallel boxes 3.5 m apart — sleeping wing and service wing — with the covered gap as the living room and the third box across one end closing the U. Any plan drawn on these footprints is buildable; plans that ignore the 2.35 m module are renders.

The 40 ft high cube is the default residential module for three measurable reasons: area per dollar (28.3 m² for a used price of $1,800–3,500 — roughly half the per-m² shell cost of a 20 ft), ceiling height (2.698 m internal, so ~2.5 m survives a 100 mm floor build-up and 100 mm ceiling insulation; the standard-height 40 ft at 2.393 m ends near 2.2 m, below many habitable-room codes), and one crane lift per 28 m² of house.

A single 40 ft HC one-bedroom is the proven format: full-width bedroom at the closed end, bathroom and kitchen amidships over one plumbing bay, living room at the door end where a glazed wall replaces the cargo doors — the one large opening you get without cutting the shell. Weight stays trivial throughout: box (3.9 t) plus a full fit-out (3–5 t) is under a third of the 28,600 kg the structure carried at sea.

Containers are designed to stack — but only one way: corner casting on corner casting. All vertical load travels down the four (six on long walls with joins) corner posts; at sea a bottom box carries 8 fully loaded units, over 200 tonnes, through those castings alone. Stack aligned, connect the castings with twist-locks or welded plates, and the structure needs no extra steel: a 2-story, 2 × 40 ft HC home (2 × 28.3 m²) is the cheapest two-level configuration there is.

The rules change the moment boxes misalign. Perpendicular stacking, offsets and cantilevers put the upper box’s corner posts onto the lower box’s roof or side rails — which are built for 300 kg point loads, not 10-tonne columns. Every such configuration needs a load path engineered back to real posts: steel columns inside the lower box, a beam bridging its top rails, or an independent frame. The same applies when a lower wall is heavily cut for glazing — remove the shear wall and the corner posts alone won’t brace the stack against wind; expect welded square-section reinforcement around the opening.

Practical 2-story numbers: floor-to-floor height is the external 2.896 m of a HC box, stairs consume ~1.5 of the 13.9/28.3 m² per level, and the upper slab is simply the lower roof — but it still needs a proper joist layer, because the 2 mm roof sheet itself is not a walking floor. Anchoring matters more with height: uplift and overturning on a light 7.8-tonne steel stack are exactly what the engineer’s stamp is for.

The box is the cheap part. Observed US ranges for a single 40 ft HC build, 2025–26 (multi-box builds scale roughly linearly on the shell items and sub-linearly on MEP):

Per square metre that is roughly $900–2,100/m² for one box — which explains the honest verdict on “cheap container homes”: a single-box studio genuinely undercuts conventional construction, while a fully finished multi-box family home lands at 70–90% of stick-built cost. What you actually buy is speed and logistics: a weather-tight structural shell in weeks, craned onto piers on sites a conventional build would struggle to reach.

The corrugated walls are not cladding — they are the structure. The ~36 mm deep corrugations act as shear webs spanning between corner posts (see what containers are made of), and every door or window cut removes load path that framing must replace. Three working rules cover most cases:

Rule 1 — frame every cut. Any opening gets a welded steel frame (typically 50–100 mm square hollow section) around its full perimeter, tied into surviving corrugations; the frame restores the panel stiffness the cut removed. Rule 2 — headers over wide openings. Openings wider than ~1.2 m need the frame’s top member sized as a genuine header carrying roof-rail load; full-wall cuts for joined boxes need a continuous beam plus posts at the joins. Rule 3 — never cut a corner post, and treat the end frames and top/bottom rails as untouchable without engineering. Doors and windows go in walls, not corners.

Sequence matters as much as sizing: weld the reinforcing frame before completing the cut where possible, or brace the opening temporarily — a freshly cut, unframed wall lets the box rack out of square, and the cargo doors stop closing as the first symptom. Existing openings are free strength: the door end already carries a full structural frame, which is why glazing the doorway is every builder’s cheapest big window (dimensions in the door dimensions guide).

In the US, an occupied container home is a dwelling under the International Residential Code like any other house — and since the 2021 IRC, Appendix AQ/related provisions explicitly recognise intermodal containers as building components. In practice approval hinges on an engineer-stamped structural package: the container’s steel is not in the code’s prescriptive span tables, so a licensed engineer must certify the modified shell — every cut, weld, stack connection and anchor.

Beyond structure, expect standard dwelling requirements: minimum room areas and a 7 ft (2.13 m) habitable ceiling (why high cubes matter), egress windows in bedrooms, insulation to the local energy code, and inspected MEP. Rules vary sharply by state and municipality — Texas, California and Florida process container homes routinely, while some local zoning boards exclude them aesthetically regardless of engineering. The practical sequence: confirm zoning first, engage the engineer second, buy the box last. Approvals can take months; the container arrives in weeks.