Ability, Permission, and Obligation
Polite Pattern for Permission and Acceptability
The pattern ～てもいいです is used to ask for or grant permission to perform an action. When attached to nouns or adjectives, it states that a substitute item or specific condition is acceptable. It literally implies "even if (you do this), it is good" and is a highly frequent polite form in everyday Japanese.
01Main Functions
Asking for Permission
By adding the question particle か to the end, the pattern becomes a polite question asking if you are allowed to do something.
このペンを使ってもいいですか。
May (I) use this pen?
Granting Permission
Used as a statement to tell someone that they are allowed to perform an action. It implies the speaker has the authority to permit it.
ここで休んでもいいです。
(You) may rest here.
Accepting a Substitute or Condition
When attached to nouns, na-adjectives, or i-adjectives, it expresses that a certain state, alternative item, or condition is acceptable.
安くてもいいです。
(It) is okay if it is cheap.
02Sentence Pattern
verb (て-form) + もいいですか
ここで写真を撮ってもいいですか。
May (I) take a picture here?
Attaches to the て-form of an action verb. Adding the question particle か turns the phrase into a polite request for permission.
verb (て-form) + もいいです
今日は早く帰ってもいいです。
(You) may go home early today.
Used as a declarative statement to grant permission. The speaker allows the listener to perform the action.
verb (て-form) + もいい？
これ、食べてもいい？
Can (I) eat this?
In casual conversations with friends or family, です is dropped. Rising intonation indicates that it is a question.
noun + でもいいですか
鉛筆でもいいですか。
Is a pencil okay?
For nouns, the form becomes でもいいです. As a question, it asks if a substitute or alternative item is acceptable.
noun + でもいいです
お茶でもいいです。
Tea is fine.
As a statement with a noun, it confirms that the substitute item is perfectly acceptable, even if it is not the primary choice.
na-adjective + でもいいですか
簡単でもいいですか。
Is it okay if it is simple?
Japanese na-adjectives act like nouns here, taking でもいいです without the な. This asks if a specific state or quality is acceptable.
i-adjective (remove い) + くてもいいです
少し古くてもいいです。
(It) is okay if it is a little old.
For i-adjectives, drop the final い and replace it with くてもいいです. This states that a certain condition is acceptable to the speaker.
03Example Sentences
このペンを使ってもいいですか。
May (I) use this pen?
Attaches to the te-form of the verb 使う to ask for permission.
ここに座ってもいいですか。
May (I) sit here?
A standard polite question asking if the action of sitting in this specific spot is allowed.
ここで写真を撮ってもいいですか。
May (I) take a picture here?
Uses the te-form of 撮る. The particle か makes it a question asking for authorization.
今日は早く帰ってもいいですよ。
(You) may go home early today.
Used as a statement to grant permission. Adding the particle よ softens the statement slightly.
辞書を見てもいいです。
(You) may look at a dictionary.
States a rule or allowance, confirming that performing this action is acceptable.
これ、食べてもいい？
Can (I) eat this?
In casual conversation with friends or family, です is dropped. Rising intonation marks it as a question.
明日でもいいですか。
Is tomorrow okay?
For nouns, the form becomes でもいいです. This uses a time-related noun to ask if an alternative time is acceptable.
鉛筆でもいいです。
A pencil is fine.
A declarative statement confirming that the alternative noun (such as using a pencil instead of a pen) is perfectly acceptable.
簡単でもいいですか。
Is it okay if it is simple?
Japanese na-adjectives act like nouns, taking でもいいですか directly to ask if a specific state is acceptable.
中古でもいいです。
(It) is okay if it is secondhand.
Used with a noun to indicate that a substitute or alternative condition is fine with the speaker.
パソコンは古くてもいいです。
(It) is okay if the computer is old.
For an i-adjective, drop the final い and add くてもいいです to show that the condition is acceptable.
値段が高くてもいいですか。
Is it okay if the price is expensive?
An i-adjective question asking if a less-than-ideal condition, such as a high cost, is acceptable.
テレビを消してもいい？
Can (I) turn off the TV?
A casual question asking for permission to perform an action.
04Comparisons
～てもいいですか vs. ～てください
These patterns are easily confused because they both involve asking for something, but they have different actors. ～てもいいですか asks if you (the speaker) are allowed to perform an action. In contrast, ～てください is a polite request asking the listener to perform the action for you.
窓を開けてもいいですか。
May (I) open the window?
窓を開けてください。
Please open the window.
～てもいいです vs. ～てはいけません
These patterns represent direct opposites when communicating rules. ～てもいいです is used to grant permission or state that something is allowed ("may" or "is okay to"). On the other hand, ～てはいけません is used to state a strict prohibition ("must not").
ここで写真を撮ってもいいです。
(You) may take a picture here.
ここで写真を撮ってはいけません。
(You) must not take a picture here.
05Nuance and Usage
The pattern ～てもいいです is a fundamental Japanese grammar structure used to express that an action, state, or substitute is acceptable. The phrase breaks down into the て-form (or で for nouns) plus も ("even") and いい ("good"). Literally, it means "Even if you do X, it is good," which translates naturally to "may" or "is okay to" in English. This literal translation perfectly captures why it is the standard way to ask for or give permission.
When you use ～てもいいです as a statement to grant permission, it inherently positions you as the authority figure allowing the action. It is perfectly natural for a parent to use with a child, a teacher with a student, or a boss with an employee. However, you should never use this pattern to grant permission to a superior or teacher, as it will come across as condescending or arrogant. If you want to offer something to a superior, it is better to use a polite request like ～てください (e.g., "Please use this").
In relaxed, casual speech with friends and family, the polite です is dropped, leaving simply ～てもいい？ for questions or ～てもいい for statements. Furthermore, native speakers often drop the particle も entirely in highly casual situations to speak more quickly. For example, 食べてもいい？ (Can I eat this?) frequently becomes 食べていい？ while maintaining the exact same meaning.
06Core Explanation
The pattern ～てもいいです is used to ask for or grant permission to perform an action.
The pattern ～てもいいです is a fundamental Japanese grammar structure used to express that an action, state, or substitute is acceptable. When paired with an action verb, it acts as the primary way to ask for or give permission. The literal meaning breaks down to "even if (you) do X, it is good," which translates naturally to "may" or "is okay to" in English.
To ask for permission, you simply add the question particle か to the end, forming ～てもいいですか ("May I...?"). This asks if it is alright for the speaker to perform an action. When granting permission, ～てもいいです is used as a statement ("You may..."). However, be careful when using this to grant permission to superiors or teachers; because it implies you hold the authority to allow the action, it can sound arrogant.
While heavily used with verbs, this pattern also attaches to nouns and adjectives to show that a condition or substitute is acceptable. For nouns and na-adjectives, the form becomes でもいいです. For example, if someone asks what you want to drink, replying 水でもいいです ("Water is fine") shows that water is an acceptable alternative. For i-adjectives, the final い is dropped and replaced with くてもいいです, as in 安くてもいいです ("It is okay if it is cheap").
In relaxed speech with close friends or family, the polite です is dropped, leaving just ～てもいい for statements or ～てもいい？ for questions with rising intonation. Furthermore, in very casual situations, the も itself is often omitted entirely. For example, 飲んでもいい？ ("Can I drink this?") frequently shortens to 飲んでいい？ while keeping the exact same meaning.
It is helpful to contrast ～てもいいです with its direct opposites. If you want to deny permission or state a prohibition, you use ～てはいけません ("must not"). If you want to say that an action is not required, rather than denying permission, you use the negative conditional ～なくてもいいです ("do not have to"). Additionally, remember that ～てもいいですか asks if you are allowed to do something, whereas ～てください asks someone else to do something.
07Common Mistakes
Wrong
ケーキを食べるもいいですか。
Correct
ケーキを食べてもいいですか。
Why: Verbs must be conjugated into the て-form before adding もいいです. It cannot be attached directly to the dictionary form.
Wrong
水を飲みもいいですか。
Correct
水を飲んでもいいですか。
Why: The pattern requires the て-form of the verb (飲んで). You cannot attach it to the ます-base (飲み).
Wrong
パソコンは古いでもいいですか。
Correct
パソコンは古くてもいいですか。
Why: To use an i-adjective with this pattern, you must drop the final い and attach くてもいいです.
Wrong
飲み物はお茶てもいいです。
Correct
飲み物はお茶でもいいです。
Why: Nouns use でもいいです, not てもいいです. The て takes a dakuten (two dots) to become で.
Wrong
先生、どうぞ私の辞書を使ってもいいです。
Correct
先生、どうぞ私の辞書を使ってください。
Why: Using ～てもいいです to grant permission implies you hold the authority to allow it. Using it toward a superior or teacher sounds arrogant; use polite request forms like ～てください instead.
Wrong
この部屋は静かてもいいですか。
Correct
この部屋は静かでもいいですか。
Why: Japanese na-adjectives like 静か act like nouns in this pattern. They take でもいいです without the な, rather than てもいいです.
08Questions
Can I use this pattern to tell my teacher they can go home?
No, that would sound very arrogant. Granting permission with ～てもいいです implies you are in a position of authority. With a teacher or boss, you should use polite request forms like ～てください to invite them to do something, rather than granting them permission.
Why do native speakers sometimes just say ていい instead of てもいいです?
In casual, everyday conversation, native speakers often drop both the polite です and the particle も to speak more quickly. So, 飲んでもいいですか (May I drink?) becomes 飲んでいい？ (Can I drink?) with rising intonation. The core meaning is exactly the same.
Does でもいいです with a noun mean it is the best choice?
Not necessarily. Using noun + でもいいです (such as 水でもいいです) often implies that while it might not be the absolute first choice, it is perfectly acceptable as an alternative or substitute. It translates closely to "Water is fine."
09Mini Practice
- 01
May (I) take a picture here?
Tap the pieces in the correct order.
- 02
鉛筆（ ）いいですか。
- 03
このケーキを（ ）いいですか。
- 04
(Addressing a teacher) 先生、私のペンを使ってもいいです。
- 05
(You) may go home early today.
Tap the pieces in the correct order.
- 06
このパソコンは安（ ）いいですか。
- 07
(Talking casually with a friend) これ、飲んでいい？
- 08
昼ごはんは簡単（ ）いいです。
Summary
Learner Summary
- The pattern verb (て-form) + もいいです means "may" or "is allowed to."
- Add the question particle か to make ～てもいいですか ("May I...?"), which is the standard way to ask for permission.
- Nouns and na-adjectives use でもいいです to show that an alternative item or condition is acceptable.
- For i-adjectives, drop the final い and attach くてもいいです (e.g., 安くてもいいです).
- Never use ～てもいいです to grant permission to a superior or teacher, as it implies you have authority over them.
- In casual speech, the polite です is dropped, and often the も is omitted entirely (e.g., 食べていい？).
10Study Map
Study Info
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