Both っぱなし and ~まま are used to express a constant or continuous action or unchanging state or event. Depending on the context they can be used interchangeably but the grammar required is different for each.

っぱなし

This phrase is a spoken one; you will not typically see it in writing.

【Verb: Stem】っぱなし
テレビを付けっぱなしで寝てしまいました。
I fell asleep with the television on.
エンジンをかけっぱなしにする。
To Leave the car running.
電車の網棚にカバンを置きっぱなしにしてしまいました。
I left my bag on the train luggage rack.
ミーティングに遅れて席がなかったので、2時間も立ちっぱなしだったよ。
I was late for the meeting left and there were no seats so I stood for 2 hours.
冷房を付けっぱなしにしておく。
Leave the air-conditioning on.

っぱなし is typically used with only a handful of verbs (the ones in the example sentences above).

まま

まま is used in both conversation and writing.

【Verb: Simple Past】まま
【Verb: Negative】まま
【Noun】のまま
電気をつけたまま寝る。
Go to sleep with the lights on.
決定を未定のまま、会議が終わりました。
The meeting ending without a decision being taken.
うちの子は食べ物を残したまま、遊びに行っちゃうのよ。
Our child just leaves food on his plate and then heads off to play.
相撲は江戸時代から変わらないままである。
Sumo remains unchanged from the Edo period.
そのままの状態。
The status quo.
そのまま受け止める。
Take at face value.
大学に進学しないまま社会人になります。
Enter society without going to university.

So what’s the difference between?

The point is whether or not an action is continually required to keep the constant state. For example:

同じシャツを着たままで出勤する。
Go to work in the same shirt.
同じシャツを着っぱなしで出勤する。
Go to work in the same shirt.

Both of the above example sentences use the structures correctly. This is because once you put on a shirt you do not need to perform any action to keep it on—you only need to put it on once.

This is not always the case. For example, to speak for three hours you have to continually perform the action of speaking. In cases where such continuous action is required we cannot use まま.

3時間も喋りっぱなしでした。
Talk non-stop for three hours.
3時間も喋ったままでした。(✘)
[Talk non-stop for three hours.]
You May Also Like

Just Finished: 〜たばかり vs 〜たところ

We now have two ways of expressing that an action has just taken place. For example, “I’ve just…

The Imperative for Honorifics

The Double Negative

ざる is another archaic form of the negative and 得ない can be used to mean “cannot do”. Put…

Nominalising Verbs (こと)

The ability to nominalise verbs is arguably the single piece of grammar that lets us move away from…