みたいだ has two main uses. First, it shows the speaker's guess from what they see, hear, or feel: 'it seems that ...'. Second, it says that something is similar to another thing: 'like ...' (春みたいだ = it is like spring). It is the spoken, casual partner of ようだ. In formal writing, ようだ is used instead.
§1Structure
Verb plain form + みたいだ (降っているみたいだ / 降ったみたいだ / いないみたいだ). い-adjective plain form + みたいだ (痛いみたいだ). な-adjective stem + みたいだ (有名みたいだ — no だ, no な). Noun + みたいだ (休みみたいだ — no だ, no の). Past and negative of な-adjectives and nouns use the plain form: 有名だったみたいだ, 休みじゃないみたいだ. みたいだ changes like a な-adjective: みたいです (polite), みたいな + noun, みたいに + verb / adjective. In casual speech だ is often dropped: 〜みたい。
§2Examples
田中さんは今日、休みみたいです。
たなかさんはきょう、やすみみたいです。
It seems Mr. Tanaka is off today.
田中さんは子どもみたいに喜んだ。
たなかさんはこどもみたいによろこんだ。
Mr. Tanaka was as happy as a child.
リンさんは頭が痛いみたいです。
リンさんはあたまがいたいみたいです。
It seems Linh has a headache.
この店は有名みたいですね。
このみせはゆうめいみたいですね。
This shop seems to be famous, doesn't it?
電気が消えています。だれもいないみたいです。
でんきがきえています。だれもいないみたいです。
The lights are off. It seems nobody is there.
きのうの夜、雪が降ったみたいですね。
きのうのよる、ゆきがふったみたいですね。
It looks like it snowed last night, doesn't it?
元気がないみたいですね。どうしたんですか。
げんきがないみたいですね。どうしたんですか。
You don't seem well. What's the matter?
今日は暖かくて、春みたいな天気だ。
きょうはあたたかくて、はるみたいなてんきだ。
It's warm today, and the weather is like spring.
§3Common mistakes
- Adding だ, な, or の before みたい. ✕ 静かだみたいです ✕ 静かなみたいです ✕ 学生のみたいです → ○ 静かみたいです ○ 学生みたいです. This is different from ようだ, which needs な and の: 静かなようです, 学生のようです.
- Forgetting to change みたい before a noun or a verb. Before a noun use みたいな, and before a verb or adjective use みたいに. ✕ 子どもみたい人 → ○ 子どもみたいな人. ✕ 子どもみたい泣きました → ○ 子どもみたいに泣きました.
- Using みたいだ for a direct impression of how something looks right in front of you. When you look at a cake and think it looks tasty, say おいしそうです. おいしいみたいです is a guess from other clues, for example when you see many people waiting in line at the shop.
§4How it's different from similar grammar
- 〜ようだ (conjecture)
- The meaning is almost the same. みたいだ is casual and used mainly in conversation. ようだ is more formal and is also used in writing. The connection is different: 留守みたいです / 留守のようです (noun), 暇みたいです / 暇なようです (な-adjective). With verbs and い-adjectives both attach to the plain form: 雨が降ったみたいです / 雨が降ったようです.
- 〜そうだ (appearance: looks like)
- そうです (appearance) gives a direct impression from how something looks now, and it attaches to the stem: このかばんは重そうです (This bag looks heavy — I am looking at it). みたいです is a guess that the speaker makes from some clue: このかばんは重いみたいです (It seems this bag is heavy — for example, the person carrying it is walking slowly).
§5How this shows up on the JLPT
In grammar-form questions, the connection is the usual point: a noun or な-adjective goes directly before みたい (病気みたいです), with no だ, な, or の. If the choices include both みたい and よう, check what is before the blank: 病気の → ようです, 病気 → みたいです. Another common point is the choice between みたいだ / みたいな / みたいに: look at the word after the blank (noun → みたいな, verb or adjective → みたいに, end of sentence → みたいだ). みたい appears often in the conversation-style questions and in listening, because it is a spoken form. In reading, decide whether it means a guess ('it seems') or a comparison ('like').
§6Quick check (3 questions)
1. Which sentence correctly says 'It seems that room is quiet'?
2. Choose the best form for the blank: 妹は歌手__上手に歌います。
いもうとはかしゅ__じょうずにうたいます。
3. In which sentence does みたい mean 'similar to / like' (a comparison), not a guess?