What Does “Nandayo” Mean in Japanese? A Detailed Guide

“Nandayo” is an often-used phrase in Japanese, so I have decided to write this blog post to explain its meaning in detail. I know that the phrase doesn’t seem to be that complicated at first. However, the translation is more complex than you might have thought. So let’s take a look at what “Nandayo” means in Japanese.

As a stand-alone expression “Nandayo” (何だよ) means “What?”, “What the heck”, or “What the hell” and is used to show surprise, dismay, or annoyance in Japanese. When “nandayo” (なんだよ) is used at the end of a sentence it adds emphasis and makes the sentence sound more empathic just like “dayo” (だよ).

Below I will cover in detail the two meanings of “Nandayo” in Japanese and will show you how to use the expression with a lot of example sentences. You can also find the translations of the most common phrases found in anime and other Japanese pop culture such as “Daisuki nandayo“, “Nandayo baka“, “Nandayo koitsu“, and “Ehe te nandayo“.

The Meaning of “Nandayo” in Japanese

The Japanese expression “Nandayo” (何だよ) consists of the word 何 (nan or nani) meaning “what“, the copula だ (da) which translates as “be, is, are“, and the sentence-ending particle よ (yo) that is used to emphasize something, but dayo (だよ) can also be seen as one word that adds emphasis.

(If you want to get to know what “dayo” means in English and how to use it Japanese check out my linked blog post.)

• What?
• Whaaaat!?
• What is …?
• What are…?
• What the hell!
• What the heck!
• What do you want?
• What’s your problem?
• I tell you!
• I’m telling you!

When used as a stand-alone phrase in Japanese “Nandayo” (何だよ) is usually used to express surprise, dismay, or annoyance. In these situations and depending on the intonation, it can be translated as a harmless and inquisitive “What?“, a shocked “Whaaaat?” or “WTF?“, all the way up to an extremely annoyed “What the heck do you want?” or “What’s your problem?“

Nandayo? Mitai no desu ka?
何だよ？見たいのですか？
What? Do you want to see it?

Nandayo??? Gakkou o sabotta no?
何だよ？？？学校をサボった？
Whaaaaat? You skipped school?

Nandayo! Miru na!
何だよ！見るな！
What the heck (do you want)? Don’t stare at me!

When “Nandayo” (何だよ) is used to talk about a thing or an event it generally translates as “What is (this thing)?“, “What are (these things)?“, “What the heck is (this thing)?“, “What the hell is going on with (this thing)?“, or “What the hell is wrong with (this thing)?“.

Nandayo kore wa?
何だよこれは？
What is this?

Ittai nandayo, kono keitai?
一体何だよ、この携帯？
What the hell is wrong with this phone?

Sono oto nandayo?
その音何だよ？
What the heck was that noise?

However, if you see “Nandayo” at the end of a sentence it has a totally different meaning. In this situation, it is most commonly written in hiragana only as なんだよ and used to add emphasis. Unfortunately, its nuance is often lost when translating the Japanese sentence to English, but you can think of it as “I tell you“, “I’m telling you“, or “…, you know“.

Choko daisuki nandayo!
チョコ大好きなんだよ！
I love chocolate, you know!

Shinpin nandayo.
新品なんだよ。
It’s brandnew, I tell you.

Soko nandayo!
そこなんだよ！
THERE it is!

How to Use “Nandayo” in Japanese – Common Phrases

“Nandayo” (何だよ, なんだよ) should only be used when talking to friends, family members, or other people you know very well since it is a casual and pretty strong phrase that can also be used to express dismay and annoyance. It shouldn’t be used in a business setting or any other formal situation.

Let’s look at some common phrases that you will often hear or see in anime and manga.

Nandayo Baka – Means “What’s Your Problem Idiot?”

“Nandayo, baka!” (なんだよ、バカ) is used as an insult and can be translated as “What’s your problem, idiot?“, “What do you want, idiot?“, or “What did you just say? Idiot!“. In anime, you might hear an evil boss say it to one of their foes or subordinates.

Nandayo, baka!
何だよ、バカ！
What’s your problem, idiot!

Nandayo? Baka!
何だよ？バカ！
What did you just say? Idiot!

Nandayo Koitsu – Means “What’s Wrong With This Guy?”

Depending on the situation and how it is said “Nandayo koitsu” (何だよこいつ) can either mean “What’s wrong with this guy?“, “WTF! What’s up with this guy?“, or “Who the hell do you think you are (to say/do this)?“. Koitsu (こいつ, コイツ, 此奴) means “this guy/gurl“, “this fellow“, or “this chap“, but also “this thing“.

Nandayo koitsu…
何だよこいつ…
What’s wrong with this guy…

Nandayo koitsu!
何だよコイツ！
WTF is wrong with this guy!!!

Nandayo, koitsu wa?
何だよ、此奴は？
Who the hell is this guy???

Daisuki Nandayo – Means “(Cause) I Love You” or “I Love It”

The phrase “Daisuki nandayo” (大好きなんだよ) means “I love you (or it)!!!“, “BECAUSE I love you (or it)”, “The thing is that I really love you (or it)”. The phrase can be used for to talk about someone or something and in this case, the nandayo (なんだよ) just adds emphasis to the whole sentence.

Daisuki nandayo!
大好きなんだよ！
(Because) I love you!!!
(Because) I love it!!!

Ehe te Nandayo – Means “What Do You Mean “Hehe”!?”

“Ehe te nandayo?” (｢えへっ｣て何だよ･･･！！) and means “What do you mean “hehe”!?“. The character Paimon from the game “Genshin Impact” uses this phrase to scold Venti even more after he just answered her question with “hehe” .

“Ehe” te nandayo?
｢えへっ｣て何だよ･･･！！
What do you mean “hehe”?

Kimi Nandayo – Means “(Because) it’s You” or “Oh it’s You”

“Kimi nandayo” (君なんだよ) can be used to emphasis that you are doing something just for her and mean “BECAUSE it’s you“. It can also be used when your run into someone or someone starts talking to you and upon recognizing them you want to show your surprise or relief by saying “Oh it’s (just) you!“.

Nandemo yaru! Kimi nandayo!
なんでもやる！君なんだよ！
I’ll do anything! Because it’s you!

Kimi nandayo! Bikkuri shita…
君なんだよ！びっくりした…
Oh it’s you! You scared me…

Kimi dayo. Kimi nandayo. Oshiete kureta.
君だよ。君なんだよ。教えてくれた。
It’s you! You are the one! The one that taught me.

What’s the Difference Between Nande and Nandayo?

The difference between “Nande” (なんで, 何で) and “Nandayo” (何だよ) is that nande means “why“, while nandayo means “what?” or “What the hell?“. Another difference is that nandayo can be added at the end of a sentence to add emphasis. Nande is usually used as a question word at the beginning of a sentence.

Nande?
なんで？
Why?

Nandayo?
何だよ？
What?

Nande Toukyou Guuru?
何で東京喰種？
Why Tokyou Ghoul?

Nandayo Toukyou Guuru?
何だよ東京喰種？
What is Tokyou Ghoul?

What might be even more confusing is the difference between “Nande da yo” (なんでだよ, 何でだよ) and “Nandayo” (何だよ, なんだよ) since both phrases can be used to express dismay or disappointment. “Nande da yo” means “But why?” or “Why the hell?“, while “Nandayo” translates as “Whaaaaat?“, or “What the hell?“.

Nande da yo
なんでだよ
But why?
Why the hell?

Nandayo
何だよ
Whaaaat?
What the hell?

If you want to know in detail what nande (なんで, 何で) means in Japanese I highly recommend you to check out my other blogpost. It includes a ton of useful and commonly used phrases in daily life as well as anime and manga!

What’s the Difference Between Nani and Nandayo?

“Nani” (何, なに) and “Nandayo” (何だよ, なんだよ) both mean “What?“. However, the difference is that nandayo is more casual and should only be used in casual conversations. “Kore wa nani?” (これは何？) and “Nandayo kore?” (何だよこれ？) both translate as “What is this?“, but the latter phrase could be considered rude.

Is Nandayo a Formal Phrase?

“Nandayo” (何だよ, なんだよ) is a causal phrase used in informal situations and spoken Japanese. The formal phrase to ask “What is it?” or “What is this?” would be “Nan desu ka?” (何ですか) or “Kore wa nan desu ka?” (これは何ですか).

Nandayo?
何だよ？
What? (casual)

Nan desu ka?
何ですか？
What is it? (formal)

Nandayo kore?
何だよこれ？
What is this? (casual)

Kore wa nan desu ka?
これは何ですか？
What is this? (formal)

Examples of How to Use Nandayo in a Japanese Sentence

If you need more examples you can also check out this blog post about the Japanese meaning of nanda (なんだ, 何だ) with another 15 example sentences.

Sou nandayo! Yes, I swear!	そうなんだよ！
Ittai nandayo? What the hell?	一体なんだよ？ いったい なんだよ？
Nandayooo Moooo Wtf? Come on!	何だよぉおもおおぉ なんだよぉお もおおぉ
Nandayo, hey!? What the hell, hey!?	何だよ、おい！？ なんだよ、おい！？
Anime daisuki nandayo! Because I love anime!	アニメ大好きなんだよ！ アニメ だいすき なんだよ！
Kitto byouki nandayo. It’s surely because he is ill.	きっと病気なんだよ。 きっと びょうき なんだよ。
Nandayo okaachan, kyou wa nichyou daze. What’s the hell, mum. It’s Sunday today.	何だよ母ちゃん、今日は日曜だぜ なんだよ おかあちゃん、きょう は にちよう だぜ
Kore ga mondai nandayo! That’s exactly the problem!	これが問題なんだよ。 これ が もんだい なんだよ。
Na…Nandayo!? W…What!?	なっ、何だよ！ なっ、なんだよ！
Nandayo kono manga? What he heck is this manga?	なんだよこの漫画？ なんだよ この まんが？
Ore wa kekkou futsuu nandayo na… I’m a pretty nomral guy, you know…	オレは結構普通なんだよな… オレ は けっこう ふつう なんだよ な…
Tsumanee tte nandayo? What do you mean “boring”?	つまんねえって何だよ つまんねえ って なんだよ
Dame nandayo! Because it is no good!	ダメなんだよ！
Nandayo kekkou kawai ja nee ka… What the…you’re damn cute…	何だよ結構可愛いじゃねえか… なんだよ けっこう かわいい じゃねえ か…
Miotoshi tte, nandayo? Forget what?	見落としって、なんだよ？ みおとしって、なんだよ？
Tomodachi nandayo! Because we are friends!	友達なんだよ！ ともだち なんだよ！
Hontou ni ima ga shiawase nandayo (Because) I’m really happy now	本当に今が幸せなんだよ。 ほんとう に いま が しあわせ なんだよ。
Nagai natsu yasumi ga suki nandayo ne Because you like long summer holidays, isn’t it?	長い夏休みが好きなんだよね ながい なつ やすみ が すき なんだよ ね