Translation guide
The English word "upstairs" can refer to a location, a direction, or a part of a building. In Japanese, the most common equivalent is 二階 (にかい), but the exact expression depends on context, such as whether you are talking about going upstairs, being upstairs, or the upstairs floor itself.
To say that someone or something is on the upper floor of a building.
Literally 'second floor'. In Japanese houses and many buildings, the upper floor is typically the second floor. Use with location particles like に or で.
The children are upstairs.
二階で寝ています。
I'm sleeping upstairs.
Means 'upper floor' and can be used for buildings with more than two floors. More general than 二階.
上の階に住んでいます。
I live upstairs.
To express movement to the upper floor.
The verb 上がる means 'to go up'. This is the most natural way to say 'go upstairs'.
二階に上がってください。
Please go upstairs.
彼は二階に上がった。
He went upstairs.
Using 行く (to go) is also possible, but 上がる is more specific to going up.
ちょっと二階に行ってくる。
I'll go upstairs for a bit.
Referring to the upstairs as a part of a house or building.
Can also mean the upstairs area as a whole, especially in a two-story house.
この家の二階は広い。
The upstairs of this house is spacious.
Literally 'second floor part', used in more descriptive or technical contexts.
二階部分を改装した。
We renovated the upstairs.
When the upper floor is not the second floor, or in buildings with many floors.
Works for any floor above the current one. Use the specific floor number if known (e.g., 三階 for third floor).
上の階で火事があった。
There was a fire upstairs.
If you know which floor, it's more natural to say 三階 (3rd floor), 四階 (4th floor), etc.
三階のトイレを使ってください。
Please use the upstairs bathroom. (if it's on the 3rd floor)
The word 上階 (じょうかい) exists but is formal and rarely used in daily conversation. Stick to 二階 or 上の階.
In English, 'upstairs' can imply the stairs themselves (e.g., 'run upstairs'). In Japanese, you usually specify the floor destination, not the stairs. To emphasize the action on stairs, use 階段 (かいだん) for stairs.
二階にトイレはありますか？
Is there a bathroom upstairs?
彼女は二階に駆け上がった。
She ran upstairs.