How to say I don't know and I don't understand in Spanish

There comes a time in every Spanish learner’s journey when you simply have to say: what!? And when that time comes, you need to be able to say I don’t understand in Spanish.

We’ve all been there—you spend countless hours in Spanish class and at home studying a new language, and, suddenly, you’re hit with something you don’t understand. What did they just say?

As embarrassing as these situations may be, there is absolutely nothing wrong with having to ask for clarification or admitting that you simply don’t understand something. In fact, it would be worse if you didn’t routinely put yourself in situations where you didn’t understand everything you heard. Full language immersion is one of the fastest ways to learn Spanish, and not understanding every single thing is one of the main reasons why it helps us improve so quickly.

With that said, you should be prepared for when you don’t understand something. Knowing how to say I don’t know in Spanish will help you get the instant feedback that you need to improve. Not only will you avoid awkward silence or a misunderstanding, but being able to vocalize that you don’t understand something in Spanish will prompt people to help you. As you’ll find out, most would be happy to rephrase or offer an alternative explanation to help you out.

So, this blog will cover 59 different ways to say I don’t know in Spanish, as well as common variations like “I’m not sure” or “I don’t understand” in Spanish. Now, you won’t have any excuses not to know how to say I don’t know! As the Spanish saying goes, “sobre aviso, no hay engaño.

You can also download your free Spanish language essentials eBook here, a trusty guide to all the Spanish basics.

Let’s get started!

Knowing how to say I don’t know in Spanish will help you get the instant feedback that you need to improve.

How to say I don’t know in Spanish

Let’s start with the basics. The very first thing you should know is that the verb “to know” is saber, which is an irregular verb that doesn’t follow typical conjugation rules. This is a common mistake among non-native speakers. In fact, there’s a whole term for heritage speakers who can’t speak Spanish well: no sabo kids.

Make sure you memorize the different conjugations for the verb saber so you avoid getting lumped into this group. Not only is it useful for saying I don’t know in Spanish, but it’s also helpful for saying what you do know! Here are the conjugations for it:

  • Yo sé
  • Tú sabes
  • Ellos saben
  • Nosotros sabemos
  • Ustedes saben
  • Ellos saben
  • Usted sabe

Now, let’s get into some common ways to say I don’t know, including helpful phrases like “I don’t know what to do” and “I don’t know yet” in Spanish.

English Spanish IPA Pronunciation
I don’t know. No sé. ˈno ˈse no seh
I don’t know that. No lo sé. ˈno lo ˈse no loh seh
I don’t know, yet. Aún no lo sé. aˈun ˈno lo ˈse ah-oohn no loh seh
I don’t know English. No sé hablar inglés. ˈno ˈse aˈβlaɾ inˈɡles no seh ah-blahr een-glehs
I don’t know what to do. No sé qué hacer. ˈno ˈse ˈke aˈseɾ no seh keh ah-sehr
I still don’t know. Todavía no sé. toðaˈβia ˈno ˈse toe-dah-vee-ah no seh
I don’t think so. No lo creo. ˈno lo ˈkɾeo no loh creh-oh
I don’t think. No creo. ˈno ˈkɾeo noh creh-oh
We don’t know. No sabemos. ˈno saˈβemos no sahbeh-mohs
I have no idea. No tengo idea. ˈno ˈtenɡo jˈðea no tehn-go e-deh-ah
I haven’t the slightest idea. No tengo la menor idea. ˈno ˈtenɡo la meˈnoɾ iˈðea no tehn-goh la meh-nor e-deh-ah
I don’t know. No conozco. ˈno koˈnosko no coh-nohs-coh

I don’t understand in Spanish

Perhaps it’s not that you don’t know, but that you don’t understand. While there’s a subtle difference in not knowing and not understanding, using different expressions will yield different results. If you say “I don’t understand,” you’ll get an explanation from the other party, thus helping you learn that which you do not (yet!) know.

A mechanic explains what needs fixing to his customer.

English Spanish IPA Pronunciation
I don’t understand. No entiendo. ˈno enˈtjendo no ehn-tee-ehn-doe
I don’t understand. No comprendo. ˈno komˈpɾendo no cohm-prehn-doe
I don’t understand that. No lo entiendo. ˈno lo enˈtjendo no loh ehn-tee-ehn-doe
I don’t understand you. No te entiendo. ˈno te enˈtjendo no teh ehn-tee-ehn-doe
I didn’t understand you. No te entendí. ˈno te entenˈdi no teh ehn-tehn-dee
Sorry, I don’t understand you. Perdón, no te entiendo. peɾˈðon | ˈno te enˈtjendo pear-dohn, no teh ehn-tee-ehn-doe
Sorry, I don’t understand you. (formal) Disculpe, no le entiendo. disˈkulpe | ˈno le enˈtjendo dees-cool-peh, no leh ehn-tee-ehn-doe
I don’t understand at all. No entiendo para nada. ˈno enˈtjendo ˈpaɾa ˈnaða no ehn-tee-ehn-doe pah-rah nah-dah
I don’t understand anything. No entiendo nada. ˈno enˈtjendo ˈnaða no ehn-tee-ehn-doe nah-dah
Sorry, I don’t understand. Perdón, no entiendo. peɾˈðon | ˈno enˈtjendo pear-dohn, no ehn-tee-ehn-doe
I don’t understand the question. No entiendo tu pregunta. ˈno enˈtjendo tu pɾeˈɣunta no ehn-tee-ehn-doe too preh-goon-tah
I don’t understand English. No entiendo inglés. ˈno enˈtjendo jnˈɡles no ehn-tee-ehn-doe een-glehs
I don’t understand why. No entiendo por qué. ˈno enˈtjendo poɾ ˈke no ehn-tee-ehn-doe pore-keh
I don’t understand what you’re saying. No entiendo lo que dices. ˈno enˈtjendo lo ˈke ˈðises no ehn-tee-ehn-doe loh keh dee-sehs
I don’t understand what they’re saying. No entiendo lo que están diciendo. ˈno enˈtjendo lo ˈke esˈtan diˈsjendo no ehn-tee-ehn-doe loh keh ehs-tah pah-sahn-doe
How’d you say? ¿Cómo? ˈkomo ‖ coh-moh
I’m not following. No te sigo. ˈno te ˈsiɣo no teh see-go
I don’t get it. No capto. ˈno ˈkapto no cap-toe
What I don’t understand is… Lo que no entiendo es… lo ˈke ˈno enˈtjendo ˈes loh keh no ehn-tee-ehn-doe ehs
I didn’t understand. No entendí. ˈno entenˈdi no ehn-tehn-dee
I didn’t understand anything. No entendí nada ˈno entenˈdi ˈnaða no ehn-tehn-dee nah-dah
How is that so? ¿Cómo así? ˈkomo aˈsi ‖ coh-moh ah-see
What are you talking about? ¿De qué hablas? de ˈke ˈaβlas ‖ deh keh ah-blahs
What do you mean? ¿A qué te refieres? a ˈke te reˈfjeɾes ‖ ah keh teh reh-fee-air-ehs
What do you mean by that? ¿Qué quieres decir con eso? ˈke ˈkjeɾez ðeˈsiɾ kon ˈeso ‖ keh key-air-ehs deh-seer cohn eh-so

I’m not sure in Spanish

Sometimes, you just fall somewhere between knowing and not knowing. In these cases, it’s important to know how to let someone know that you have an idea but are not entirely sure. Here are a few helpful ways to say I’m not sure in Spanish.

I'm not sure in Spanish.

English Spanish IPA Pronunciation
I’m not sure. No estoy seguro. ˈno esˈtoj seˈɣuɾo no ehs-toy seh-goo-roh
We’re not sure. No estamos seguros. ˈno esˈtamos seˈɣuɾos no ehs-tah-mohs seh
It’s not all clear to me. No me queda del todo claro. ˈno me ˈkeða ðel ˈtoðo ˈklaɾo no meh keh-da dell toh-doh clah-ro
I have my doubts. Tengo mis dudas. ˈtenɡo miz ˈðuðas tehn-go mees doo-dahs
Let me think about it. Déjame pensarlo. ˈdexame penˈsaɾlo deh-hah-meh pehn-sar-lo
I’m not certain. No tengo la certeza. ˈno ˈtenɡo la seɾˈtesa no tehn-go la sehr-teh-za
It’s unclear. No está claro. ˈno esˈta ˈklaɾo no ehs-tah cla-roh
I don’t know for certain. No lo sé con seguridad. ˈno lo ˈse kon seɣuɾiˈðað no lo seh cohn seh-goo-ree-dad
I’m not 100% sure. No estoy 100% seguro. ˈno esˈtoj ˈsjen seˈɣuɾo no ehs-toy see-ehn pore see-ehn-toe seh-goo-ro

Slang for I don’t know in Spanish

If you’ve been reading our Spanish guides for a while, you know that we like to prepare you to Speak Spanish as naturally as possible. And in order to do that, you’re going to need some Spanish slang! Here are some slang and more casual ways to say I don’t know, I don’t understand, or I’m not so sure in Spanish.

English Spanish IPA Pronunciation
To know. Saber saˈβeɾ sah-ber
Who knows. Sepa. ˈsepa seh-pah
Who knows. Quién sabe. ˈkjen ˈsaβe key-ehn sah-beh
Nobody knows. Nadie sabe. ˈnaðje ˈsaβe nah-dee-eh sah-beh
God knows. Dios sabe. ˈdjos ˈsaβe dee-ohs sah-beh
No idea. Ni idea. ni iˈðea nee e-deh-ah
Let me check. Déjame ver. ˈdexame ˈβeɾ deh-hah-meh-vehr
I wouldn’t know what to tell you. No sabría decirte. ˈno saˈβɾia ðeˈsiɾte no sah-bree-ah deh-seer-teh
I don’t get you. No te agarro la onda. ˈno te aˈɣaro la ˈonda no teh ah-gah-roh la ohn-dah
I didn’t catch that. No te caché. ˈno te kaˈʧe no teh cah-cheh
It defeats me. Me gana. me ˈɣana meh gah-nah
I wish I knew. Ojalá supiera. oxaˈla suˈpjeɾa oh-hah-lah soo-pee-air-ah
Don’t even look at me. A mí ni me veas. a ˈmi ni me ˈβeas ah me nee meh veh-ahs

Example I don’t know sentences in Spanish

If you’re having a hard time putting all this new vocabulary in context, do not worry! We’ve got some handy sample sentences for you to sink your teeth into. And while there’s nothing to apologize for, you may want to work in some ways to say I’m sorry to be extra polite–make sure to check out our guide to saying sorry in Spanish!

English Spanish IPA Pronunciation
Sorry, I don’t know how to speak English. Perdón, no sé hablar inglés. peɾˈðon | ˈno ˈse aˈβlaɾ inˈɡles ‖ pear-dohn, no seh ah-blahr een-glehs
I’m sorry, I don’t know. Disculpa, no lo sé. disˈkulpa | ˈno lo ˈse ‖ dees-cool-pah, no loh seh
No, I don’t know who that is. No, no sé quién es ella. ˈno | ˈno ˈse ˈkjen ˈes ˈeʝa ‖ no, no seh key-ehn ehs eh-yah
I don’t know how to get there No sé cómo llegar allí. ˈno ˈse ˈkomo ʝeˈɣaɾ aˈʝi ‖ no seh coh-mo yeh-gar ah-e
I don’t think it will rain. No creo que llueva ˈno ˈkɾeo ˈke ˈʝweβa no creh-oh keh you-eh-vah
Could you repeat that for me? I didn’t understand you. ¿Me lo podrías repetir? No te entendí. me lo poˈðɾiaz repeˈtiɾ ‖ ˈno te entenˈdi ‖ meh loh poh-dree-ahs ex-plee-car? no teh ehn-tehn-dee
Could you explain it to me again? I still don’t understand. ¿Me lo podrías volver a explicar? Aún no entiendo. me lo poˈðɾiaz βolˈβeɾ a ekspliˈkaɾ ‖ aˈun ˈno enˈtjendo ‖ meh lo poh-dree-ahs vol-vehr ah ex-plee-car? ah-oon no ehn-tee-ehn-doe
Could you help me with the math homework? I don’t understand anything. ¿Me puedes ayudar con la tarea de matemáticas? No entiendo nada. me ˈpweðes aʝuˈðaɾ kon la taˈɾea ðe mateˈmatikas ‖ ˈno enˈtjendo ˈnaða ‖ meh poo-eh-dehs ah-you-dar cohn la tah-reh-ah deh mah-teh-mah-tee-cahs? no ehn-tee-ehn-doe nah-da
—Do you know what time the bus comes by?

—No, I don’t know.
—¿Sabes a qué hora pasa el camión?

—No, no sé.
—ˈsaβes a ˈke ˈoɾa ˈpasa el kaˈmjon ‖

—ˈno | ˈno ˈse ‖
—sah-behs ah keh oh-rah pah-sah elle cah-me-ohn?

—no, no seh
—When did you meet?

—I’m not sure, I think maybe 7 years ago.
—¿Cuándo se conocieron?

—No estoy seguro, creo que hace 7 años.
—ˈkwando se konoˈsjeɾon ‖

—ˈno esˈtoj seˈɣuɾo | ˈkɾeo ˈke ˈase ˈsjete ˈaɲos ‖
—coo-ahn-doe seh coh-noh-see-air-ohn?

—no ehs-toy seh-goo-roh, creh-oh keh ah-seh see-eh-teh ah-nyohs
—Who let the door open?

—Who knows.
—¿Quién dejó la puerta abierta?

—ˈkjen deˈxo la ˈpweɾta aˈβjeɾta ‖

—ˈsepa ‖
—key-ehn deh-hoh la poo-air-tah ah-bee-air-tah?

Okay, repeat it to me cause I still don’t get you. A ver, repítemelo porque todavía no te agarro la onda. a ˈβeɾ | reˈpitemelo ˈpoɾke toðaˈβia ˈno te aˈɣaro la ˈonda ‖ ah-vehr, reh-pee-teh-meh-lo pore-keh toh-dah-vee-ah no teh ah-gah-roh la ohn-dah
—Whose dog is that?

—Oh, I wouldn’t know what to tell you,
—¿De quién es ese perro?

—Uy, no sabría decirte.
—de ˈkjen ˈes ˈese ˈpero ‖

—ˈuj | ˈno saˈβɾia ðeˈsiɾte ‖
—deh key-ehn es eh-seh peh-roh?

—oo-e, no sah-bree-ah deh-seer-teh
—Who ate my ice cream?

—Don’t even look at me.
—¿Quién se comió mi helado?

—A mí ni me voltees a ver.
—ˈkjen se koˈmjo mj eˈlaðo ‖

—a ˈmi ni me βolˈtees a ˈβeɾ ‖
—key-ehn seh coh-mee-oh me eh-la-doh?

—ah me ne meh vohl-teh-ehs ah vehr

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Now you know

Learning how to say I don’t know in Spanish is one of those things that requires minimum effort but comes with a huge payoff. Once you’ve gotten the hang of a few of these phrases, you’ll be able to quickly communicate that you don’t know or don’t understand something and need some extra help understanding.

The last thing you want is to be in a situation where you don’t understand something and you don’t know how to say that you don’t understand!

If you enjoyed this article, make sure to check out our other guides to helpful Spanish phrases, such as asking where the bathroom is in Spanish and how to say goodnight in Spanish.

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