Learn Hardcore Chinese: xiàbān yǐhòu wǒ xiǎng shuì yíhuìr.

Putting 以后 in front, as in 以后下班, would sound like “in the future, (I will) get off work”, which is a different meaning and still feels incomplete.

So:

下班以后我想睡一会儿。
After work, I want to sleep for a bit.

But:

以后我不想这么晚下班。
In the future, I don’t want to get off work this late.

Here 以后 modifies the whole sentence (“in the future”), not the single verb 下班.

Can I also say 下了班以后 or 下班了以后? Are they different from 下班以后?

Yes, you’ll often hear:

下了班以后
下班了以后

They both sound natural.

Subtle points:

下班以后 – more neutral, often used in written and spoken Chinese.
下了班以后 – emphasizes the action of having finished work (the 了 attaches to the verb 下, marking completion).
下班了以后 – 了 is more like a sentence/ state change marker inside the phrase; still essentially means “after (it is) off work.”

In everyday speech, the differences are very small. All three can usually be understood simply as “after work.”

Is the word order 下班以后我想睡一会儿 the only correct one? Where else can I put 下班以后?

Chinese time expressions are flexible. The main common patterns here are:

下班以后，我想睡一会儿。
(Time expression at the very beginning.)
我下班以后想睡一会儿。
(Time expression after the subject.)

Both are natural. Putting 下班以后 after the verb is usually not correct:

✗ 我想睡一会儿下班以后。 – wrong.

You can remember: general time words usually go before the main verb (often right after the subject or at the very start of the sentence).

Why is there no 在 (zài) before 下班以后? Could I say 在下班以后我想睡一会儿?

In this kind of time phrase, 在 is not needed and usually sounds unnatural.

下班以后我想睡一会儿。 ✔
在下班以后我想睡一会儿。 ✗ (awkward / not idiomatic)

For time expressions like “after work, before dinner, tomorrow, next week,” Chinese generally does not use 在:

吃饭以前先洗手。 – Wash your hands before eating.
明天我去北京。 – I’ll go to Beijing tomorrow.

在 is used more for locations (在学校, “at school”) or when emphasizing being in the middle of an action (在吃饭, “be eating”), not for simple “after X / before Y” time phrases.

What exactly does 想 (xiǎng) mean here? Is it “want to” or “think (that)”?

In this sentence, 想 means “to want to / to feel like (doing something)”.

我想睡一会儿。
I want to sleep for a bit. / I feel like taking a short nap.

想 can mean:

to want to:
- 我想喝水。 – I want to drink water.
to think / to miss (different usages, not in this sentence):
- 我想他不来了。 – I think he’s not coming.
- 我想你。 – I miss you.

Here, because 想 is followed by a verb phrase (睡一会儿), and the context is about a desire after work, it’s clearly the “want to” meaning.

Could I use 要 (yào) or 会 (huì) instead of 想? How would the meaning change?

Yes, but the nuance changes:

要 (yào) – more decided / planned:
- 下班以后我要睡一会儿。
  After work I’m going to sleep for a bit.
  → Sounds like a fairly firm plan or intention.
会 (huì) – more like “will (probably)” / prediction:
- 下班以后我会睡一会儿。
  After work I’ll (probably) sleep for a bit.
  → Sounds like you’re predicting what you’ll do, not stressing desire.
想 (xiǎng) – focuses on desire / wish:
- 下班以后我想睡一会儿。
  After work I want to sleep for a bit.
  → Emphasizes what you feel like doing.

All three are grammatically OK, but 想 fits best if you’re expressing what you want to do.

Why is it 睡 and not 睡觉? What’s the difference between 睡 and 睡觉 here?

Both are possible:

下班以后我想睡一会儿。
下班以后我想睡觉。

Nuances:

睡 (shuì) alone is the verb “to sleep”.
睡觉 (shuìjiào) is also “to sleep,” but often thought of as the full verb phrase “go to sleep / sleep (as an activity).”

In your sentence:

我想睡一会儿 highlights the duration (sleep for a bit).
我想睡觉 is more like “I want to sleep” (less specific about how long).

You could also say:

我想睡一会儿觉。 – also natural, combining both: “I want to sleep for a bit.”

What does 一会儿 (yíhuìr) mean exactly? How long is “a bit”?

一会儿 means “a little while / a short time / a bit.”

It’s deliberately vague; it just means not long. Depending on context and speaker, it could be:

a few minutes,
10–20 minutes,
maybe half an hour or so.

Here, 睡一会儿 implies a short nap, not a full long sleep.

Some related patterns:

等我一会儿。 – Wait for me a bit.
我们聊一会儿。 – Let’s chat for a while.

What is the 儿 (r) doing in 一会儿? Must I pronounce or write it?

The 儿 is the “erhua” (r-coloring) often used in northern Mandarin (especially Beijing).

一会儿 is pronounced yíhuìr in northern speech.
In many other regions, people just say and write 一会 (yíhuì) without 儿.

Both 一会儿 and 一会 are understood everywhere. For standard written Mandarin, 一会儿 is very common, but 一会 is also seen.

So:

Pronunciation: yíhuìr (with a light r at the end), or yíhuì.
Meaning: exactly the same.

Why is 一会儿 pronounced yíhuìr and not yīhuìr? What tones does it have?

This is due to tone sandhi for 一 (yī).

Rule:
一 changes tone depending on what follows:

Before a 4th-tone syllable, it becomes 2nd tone (yí).
Before a 1st, 2nd, or 3rd tone, it becomes 4th tone (yì), in many cases.

In 一会儿 (yíhuìr):

会 (huì) is 4th tone.
So 一 changes from yī (1st) to yí (2nd).

Result:

一会儿 → yí huì r
(一 = 2nd tone, 会 = 4th tone, 儿 is neutral tone.)

Why is there no 了 (le) after 睡? Could I say 我想睡了一会儿?

In your original sentence, you’re talking about something you want to do in the future (after work), so you do not use 了 to mark completion:

下班以后我想睡一会儿。 ✔
(Desire for a future action.)

了 usually marks completed action or a change of state.
我想睡了一会儿 would normally be understood as past/completed:

我想睡了一会儿。 – This sounds like
“I (once) wanted to sleep for a bit” or
“I thought I had slept for a while,”
depending on context—awkward without more context.

If you want to say you did sleep a bit after work:

下班以后，我睡了一会儿。
After work, I slept for a bit.

Notice that in this case 想 disappears, and 了 attaches to 睡 to mark completed action.

Can I drop 我 or 下班以后 in this sentence?

Yes, Chinese often drops things that are clear from context.

Dropping 我 (subject):
If it’s clear that you are the one speaking about your own plan:
- 下班以后想睡一会儿。
  After work (I) want to sleep for a bit.
This is common in informal speech or when the subject is obvious.
Dropping 下班以后 (time phrase):
If the time is already understood:
- 我想睡一会儿。
  I want to sleep for a bit.
In a conversation like:
- A: 你下班以后做什么？ – What will you do after work?
- B: 我想睡一会儿。 – I want to sleep for a bit.
You don’t have to repeat 下班以后 in the answer.

What’s the difference between 睡一会儿 and 睡一下?

Both express a short action, but with a slightly different feel:

睡一会儿 – sleep for a (short) while.
Emphasizes duration (some minutes/period of time).
睡一下 – literally “sleep once / sleep a bit.”
More like just “sleep a little”, lighter, less specific about time; sometimes sounds like “just lie down / rest a bit.”

In practice:

For a short nap, 睡一会儿 is more common and explicit.
睡一下 is possible but less common; people more often say:
- 躺一下。 – Lie down a bit.
- 休息一下。 – Rest a bit.

So in your sentence, 睡一会儿 is the most natural.