Nani and nan in Japanese: meaning and when to use

the kanji 何 means “what” and has two very common readings: なに (nani) and なん (nan). In general, use nani when 何 functions as an interrogative word before particles like を, が, and に; use nan before です, の, and many counters or units, such as 時, 人, 歳, and 枚.

The choice does not depend on formality. It depends on the structure that comes after 何 and, in some cases, on an established combination. Learning the most common patterns is more useful than trying to translate each character in isolation.

What do nani and nan mean in Japanese?

Nani and nan are not two words with opposite meanings. They are readings of the same kanji, 何, used to ask “what”, “which”, or “how many”, depending on the construction.

The initial material Irodori from the Japan Foundation explicitly presents the two readings of 何: なん with ですか and in combinations like 何歳 and 何時; なに with particles in examples like 何を and 何が.

This table is a practical rule for beginners. There are combinations that need to be learned as a unit, and 何で deserves special attention because the reading can change the interpretation.

When to use nani (なに)

Use なに when 何 appears as an interrogative before particles that indicate its function in the sentence. This occurs frequently before を, が, に and も.

何を飲みますか。
なにを のみますか。
Nani o nomimasu ka?
What are you going to drink?

何が必要ですか。
なにが ひつようですか。
Nani ga hitsuyō desu ka?
What is necessary?

何にしますか。
なにに しますか。
Nani ni shimasu ka?
Which one will you choose?

The same pattern appears in 何か (nanika, “something” or “some thing”) and 何も (nanimo). In negative sentences, 何も usually means “nothing”: 何も食べません (Nanimo tabemasen, “I don’t eat anything”). The Japan Foundation registers 何か as なにか and 何に as なにに.

To understand how these words fit into a complete question, see the guide on questions in japanese and the overview of japanese particles.

When to use nan (なん)

Use なん before です and だ. In that environment, the short form makes pronunciation natural:

これは何ですか。
これは なんですか。
Kore wa nan desu ka?
What is this?

あれは何だった？
あれは なんだった？
Are wa nan datta?
What was that?

The article on です in Japanese explains the difference in register between です and だ and their inflected forms.

Nan also appears in various combinations with counters, time, and quantity:

It's not enough to see a noun after 何 and automatically choose nan. Learn each frequent combination with its reading. The guide to Japanese kanji shows how to study readings within words and contexts, instead of memorizing isolated values.

Why is 何の read as nanno?

The combination 何の is read なんの (nanno) asks “what”, “which”, or “of what” before a noun:

What book is this?
What book is this?
Kore wa nanno hon desu ka?
What book is this?

What is the celebration?
What is the celebration?
Nanno oiwai desu ka?
What is the occasion of the celebration?

The second example and its reading appear in Irodori in an activity about celebrations. It shows why “particle after 何” is only an initial guideline: の forms a well-established combination with なん.

何で: nanide or nande?

When で marks instrument, means, or transportation, the reading clearly taught to beginners is なにで (nanide):

How do you come to school? / By what means do you come?
How do you come to school? / By what means do you come?
Gakkō made nanide kimasu ka?
How do you come to school? / By what means do you come?

This usage is confirmed by Irodori when explaining questions about means and transportation.

In everyday speech, なんで (nande) is widely used with the meaning of “why”. Since the writing can be identical, context and pronunciation resolve the interpretation. To avoid ambiguity when asking for a reason, beginners can also use どうして (dōshite) or Why (naze).

Therefore, the old phrase What shall we eat this cake with?, with reading nani de, it doesn't ask “which cake”. It asks “What are we going to eat this cake with?”, for example, with a fork or spoon.

Common mistakes when choosing nan or nani

• Choosing by formality: nani is not simply formal and nan is not simply informal.
• Applying a rule without exceptions: 何を and 何が use nani, but 何の uses nan.
• Ignoring compound words: forms like 何時 and 何人 should be learned as combinations.
• Confusing 何で: nanide asks about means or instrument; nande usually asks for reason in speech.
• Translating 何 always as “what”: with counters, it can mean “how many”; before a noun, it can correspond to “which” or “what kind of”.

Short dialogue with nani and nan

A: これは何ですか。
Kore wa nan desu ka?
What is this?

B: It's a Japanese sweet.
Nihon no okashi desu.
It's a Japanese sweet.

A: What's inside?
Nani ga haitte imasu ka?
What's inside?

B: It has sweet bean paste.
Anko ga haitte imasu.
It has sweet bean paste.

In the first turn, What is it? uses nan. In the second question, What uses nani because が marks the element being sought. The analysis follows the same process presented in the guide to Japanese sentence formation.

Commented exercise

Choose なに or なん and then check:

1. What is this (　)? — なん, because it comes before です.
2. What did you buy (　)? — なに, because it comes before the particle を.
3. How many people are coming (　)? — なん, forming 何人 (nannin).
4. Which one will you choose (　)? — なに, before the particle に.
5. What kind of movie is this (　)? — なん, forming 何の (nanno).

The mental rule is: start with nani before particles and nan before です, の, and counters; then memorize the combinations you encounter. To review the foundation that supports these examples, consult the Basics of Japanese Grammar.