Reading Japanese Floor Plans｜1R, 1K, 1DK and 1LDK Explained
What actually separates a 1K from a 1DK, how many square metres a jō is, and what the symbols on a floor plan mean. The basics you need to read a Japanese listing correctly, with a real sense of the sizes involved.
Reading Japanese Floor Plans
A listing that says "1LDK / 42.5㎡ / 洋6.0 / DK8.0" looks like a cipher the first time you see it. The rules are actually simple. Once you understand them, you can rule an apartment out before you ever go and see it — which saves a lot of wasted trips.
What the numbers and letters mean
Japanese layout notation is the number of rooms + the type of non-room space.
| Symbol | Meaning |
|---|---|
| Number | How many rooms are usable as bedrooms |
| R | Room. Kitchen is not partitioned off from the living space |
| K | Kitchen. A separate kitchen area |
| DK | Dining Kitchen. Big enough to eat in |
| LDK | Living Dining Kitchen. Big enough to relax in as well |
So "2LDK" means two rooms plus one living-dining-kitchen — three spaces in total.
The K / DK / LDK boundary is defined by size
This is the part that trips people up most. K, DK and LDK aren't loose descriptions of atmosphere — the minimum sizes are set by fair trade regulations.
| Rooms | Minimum to be called DK | Minimum to be called LDK |
|---|---|---|
| 1 room | 4.5 jō | 8 jō |
| 2+ rooms | 6 jō | 10 jō |
Which gives you:
- 1K — kitchen under 4.5 jō. Essentially just workspace for cooking
- 1DK — kitchen 4.5 jō or more. A small table will fit
- 1LDK — kitchen 8 jō or more. A sofa and a table can coexist
The rent gap between a 1K and a 1DK is, in practice, the price of "can you fit a table". That framing makes the difference much easier to accept.
Converting jō, tatami and square metres
If "6 jō" means nothing to you, this conversion is worth memorising.
1 jō ≒ 1.62㎡
| Jō | Square metres | What it feels like |
|---|---|---|
| 4.5 jō | ~7.3㎡ | A single bed and a small desk fills it |
| 6 jō | ~9.7㎡ | The standard for living alone. Bed, desk, storage |
| 8 jō | ~13.0㎡ | A sofa fits |
| 10 jō | ~16.2㎡ | Dining set plus sofa |
One caveat: the jō is not a fixed unit across Japan. The Edo-ma standard used around Tokyo is about 1.55㎡; the Kyō-ma used in the Kansai region is about 1.82㎡. The same "6 jō" can differ by more than a full square metre. When you want to compare accurately, use ㎡, not jō.
What "exclusive area" includes and excludes
The "42.5㎡" in a listing is the exclusive (private) floor area. If you don't know what's counted, the place will feel smaller than you pictured.
Included: rooms, kitchen, bathroom, toilet, entryway, hallway, indoor storage
Excluded: balconies, verandas, lofts, shared corridors
Balconies double as fire escape routes and are legally shared space, so they don't count. A 42.5㎡ apartment with a balcony does not have more indoor space because of it.
Lofts also don't count toward the exclusive area, though they're genuinely useful for storage. Note the 1.4m ceiling height limit — it makes them impractical as living space.
Floor plan symbols
Knowing these turns a floor plan from a sketch into real information.
| Symbol | Meaning |
|---|---|
| CL | Closet |
| WIC | Walk-in closet |
| SB | Shoe box (shoe cupboard) |
| PS | Pipe space (plumbing — cannot be moved) |
| MB | Meter box |
| UB | Unit bath (moulded bathroom module) |
| R | Refrigerator space |
| W | Washing machine space |
PS eating into the corner of a room is extremely common. A plan may show a neat rectangular 6-jō room while the actual space has a chunk missing from one corner, which constrains where furniture can go.
Recommendations by household
| Household | Suggested | Why |
|---|---|---|
| Living alone / student | 1R / 1K | Easy to clean, cheaper to heat and cool |
| Living alone + remote work | 1DK / 1LDK | Separates where you sleep from where you work |
| Two people | 1LDK / 2DK | If your schedules differ, 2DK lets you split rooms |
| Two people + frequent guests | 2LDK | Gives you real shared space |
If you work from home at all, upgrading from a 1K to at least a 1DK is strongly worth it. When your bedroom and your office are the same room, you never mentally clock off. If ¥10,000 a month solves that, it's a good investment.
Filtering by layout in practice
In Sumu Machi you can specify layouts from the left panel filters.
- Search for the area you want on the homepage
- Open the layout category in the left panel
- Select multiple candidates (1K and 1DK together, for instance)
Multi-select is the point here. Restricting to "1K only" makes you miss listings. Tick 1K, 1DK and 1LDK, then compare the square metres and rents of what comes back — that's how you build a feel for the market.
The display information category also lets you set a floor area range, which is how you find "a 1K that happens to be large". Area is a more honest number than layout notation.