10 Ways to Say ‘I Don’t Know’ in Spanish

You’re here to improve your communication skills and express ways to say “I don’t know” in Spanish. Lucky for you, we’ve got 10 popular Spanish expressions to use in your conversations.

Get ready to expand your vocabulary and learn new ways to express yourself. 

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10 Ways to Say “I Don’t Know” in Spanish

The following phrases show the English translation, a short explanation, as well as useful examples you can imitate in speech. How many of them will you use?

1. No tengo ni idea

English: I have no idea

This phrase is similar in both Spanish and English. Use it when you have no clue about something someone’s asking you.  

– Emily, ¿sabes cuál es la comida favorita de Mario?
Emily, do you know what Mario’s favorite food is?

– La verdad, no tengo ni idea.
Honestly, I have no idea.

2. Lo volveré a revisar y te aviso

English: I’ll double check and let you know

When you’re not sure about something but don’t want to say you don’t know directly, this is a great option.

– ¿A qué hora sale nuestro vuelo mañana?
What time does our flight leave tomorrow?

– Lo volveré a revisar y te aviso, pero estoy casi seguro que temprano.
I’ll double check and let you know, but I’m certain it’s early in the morning.

3. No estoy cien por ciento seguro

English: I’m not a hundred percent sure 

Use this phrase in Spanish the same way you would in English to express uncertainty. 

– James, ¿a qué hora se ve el atardecer aquí?
James, what time can we see the sunset here?

–  Creo que a las 6:00 pm, pero no estoy cien por ciento seguro.
I think at 6:00 pm, but I’m not a hundred percent sure.

4. Déjame revisarlo y te aviso

English: Let me check on that and I’ll let you know

Another way to say “I don’t know” in Spanish without sounding rude is by telling someone you’ll check it out. This phrase is useful when you know where to find the answer but don’t really have it in mind.

–  ¿Cuál es el itinerario para mañana? ¿Iremos a comer al centro de la ciudad?
What’s our itinerary for tomorrow? Are we going to eat downtown?

– Déjame revisarlo y te aviso, pero creo que iremos al centro en dos días.
Let me check on that and I’ll let you know, but I think that we’ll go downtown in two days.

5. He estado pensando exactamente lo mismo

English: I’ve been wondering the same thing

A great way of saying “I don’t know” in Spanish without letting the other person realize it is to say that you’re wondering the same thing. This will put you two on the same level and may even motivate you to look for the answer.

– Creo que Matt se escapó de su casa para ir a la casa de un amigo, ¿sabes algo de eso?
I think Matt sneaked out of his house to go to a friend’s house, do you know anything about it?

– De hecho he estado pensando exactamente lo mismo, podríamos preguntarle a su hermana.
In fact I’ve been wondering the same thing, we could ask his sister.

6. La verdad, no estoy seguro

English: Honestly, I’m not sure

This phrase is super useful when you don’t know the answer and don’t want to try to make something up. It’s a very practical way of saying “I don’t know” in Spanish, without much detour.

– ¿Sabes qué tan lejos de aquí está la playa?
Do you know how far from here the beach is?

– La verdad, no estoy seguro. Lo buscaré en Google.
Honestly, I’m not sure. I’ll Google it.

7. Quién sabe

English: Who knows?

In Spanish, this small expression is used more as an affirmation than a question. Use it when you’re trying to say that you don’t know, and don’t think anyone else does either.

– ¿Crees que llueva hoy en la tarde? El cielo se ve un poco nublado.
Do you think it’ll rain in the afternoon? The sky looks a little cloudy.

– Quién sabe. Puede que sí o puede que no.
Who knows. It might or might not.

8. Déjame averiguarte

English: Let me find out for you

This one’s another polite way of saying you don’t have the answer to someone’s question, but that you’d be pleased to help them find out.

– ¿Sabes qué hora cierra el supermercado?
Do you know at what time does the supermarket close?

– Déjame averiguarte, creo que tienen el horario en su página web.
Let me find out for you, I think they have their closing hours in their website.

9. No he tenido tiempo de pensar en eso todavía

English: I haven’t had time to think that through yet

If you simply don’t know something because you’ve been too busy to do any research, this expression is perfect. It would work with a co-worker who’s been asking you if you know anything about the topic your boss assigned both of you a few days ago, for example.

– Hey, ¿ya revisaste los resultados de la investigación de mercado?
Hey, have you already reviewed the results of the market research?

– Perdona, no he tenido tiempo de pensar en eso todavía. He estado algo ocupada con otras cosas.
Sorry, I haven’t had time to think that through yet. I’ve been kind of busy with other things.

10. Eso es exactamente lo que he estado tratando de responder

English: That’s exactly what I’ve been trying to answer

This is a simple way of saying “I don’t know” in Spanish without directly admitting that you don’t know. You can use it when you want the conversation to flow while you try to find the answer with the person who’s asking you.

– ¿Crees que algún día sabremos si hay vida en otros planetas?
Do you think that someday we’ll know if there ‘s life on other planets?

– Eso es exactamente lo que he estado tratando de responder. Ya veremos.
That ‘s exactly what I’ve been seeking to answer. We’ll see.

Popular Idioms That Mean “I Don’t Know” in Spanish

Now that we’ve seen some synonyms for “I don’t know” in Spanish, let’s see some examples of common idioms containing that phrase or expression.

Spanish	English
No sé cómo perdieron, me mata.	I don’t know how they lost, it beats me.
No sé de qué estás hablando, literalmente no tengo idea.	I don’t know what you’re talking about, literally I have no idea.
No sé ni lo más mínimo de relaciones, nunca he estado en una.	I don’t know the first thing about relationships, I’ve never been in one.
No lo conozco en absoluto.	I don’t know him from Adam.
No lo sé, ¿cómo debería hacerlo?	I don’t know, how should I?

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