I don't know
in SpanishNo sé
/NOH SEH/
This is the most direct, common, and universally understood way to say 'I don't know' in Spanish. It's a fundamental phrase you can use in any situation, from casual conversations to formal settings.
A simple shrug is the universal body language for 'No sé.' It's a gesture that perfectly matches the phrase in any Spanish-speaking country.
💬Other Ways to Say It
No lo sé
/noh loh SEH/
This version literally means 'I don't know it.' The 'lo' refers to a specific piece of information. It's often used interchangeably with 'No sé,' but adds a slight emphasis that you're talking about a particular fact.
No tengo ni idea
/noh TEN-goh nee ee-DEH-ah/
A very common and emphatic way to say 'I have no idea.' It's much stronger than a simple 'No sé' and implies complete lack of knowledge.
Ni idea
/nee ee-DEH-ah/
This is the short, snappy version of 'No tengo ni idea.' It's the Spanish equivalent of just saying 'No idea!' or 'Beats me!'
No estoy seguro/a
/noh ehs-TOY seh-GOO-roh/ah/
This means 'I'm not sure.' It's a softer, less definitive way to express uncertainty. Remember to use 'seguro' if you're male and 'segura' if you're female.
No sabría decirte
/noh sah-BREE-ah deh-SEER-teh/
A polite and slightly more formal phrase meaning 'I wouldn't know how to tell you.' The '-te' ending is for speaking to one person informally ('tú'). For formal situations, you'd say 'No sabría decirle.'
Quién sabe
/kyen SAH-beh/
This literally translates to 'Who knows?' It's used to imply that not only do you not know, but perhaps nobody knows, or the answer is up to fate.
A saber
/ah sah-BEHR/
This is a very common expression in Spain, with a similar meaning to 'Quién sabe.' It's a short, idiomatic way to say 'Who knows?' or 'It's anyone's guess.'
Estoy en blanco
/ehs-TOY en BLAHN-koh/
Literally 'I'm in white,' this is the perfect equivalent of 'I'm drawing a blank.' It means you feel you should know the answer, but you just can't remember it at the moment.
🔑Key Words
Key Words to learn:
📊Quick Comparison
Choosing the right way to say 'I don't know' depends heavily on the context and how you want to sound. Here’s a quick comparison of the most common options.
| Phrase | Formality | Best For | Avoid When |
|---|---|---|---|
| No sé | Neutral | Almost any situation; it's the universal default. | You want to sound extra polite or offer a solution in a professional setting. |
| Ni idea | Very Informal | Casual chats with friends when you're completely clueless. | Speaking with your boss, a professor, an elder, or anyone you'd address as 'usted'. |
| No estoy seguro/a | Neutral | Expressing uncertainty or when you have a guess but aren't 100% sure. | You want to give a quick, direct 'no' to a simple question. |
| No sabría decirle | Polite / Formal | Customer service, professional environments, or showing respect. | Joking around with close friends; it would sound overly formal and stiff. |
📈Difficulty Level
Very easy for English speakers. Both 'no' and 'sé' (like the 'se' in 'sell') are simple, familiar sounds.
The phrase itself is simple, but it comes from the irregular verb 'saber,' which requires some memorization. The main challenge is knowing not to use 'conocer.'
While the phrase is simple, knowing when to be direct with 'No sé' versus using a softer or more polite alternative requires social awareness. The cultural context is moderately complex.
Key Challenges:
- Distinguishing between 'saber' and 'conocer'
- Choosing the appropriate level of formality (e.g., 'No sé' vs. 'Ni idea' vs. 'No sabría decirle')
💡Examples in Action
¿Sabes dónde está la estación de tren? — Lo siento, no sé.
Do you know where the train station is? — I'm sorry, I don't know.
Oye, ¿quién ganó el partido anoche? — Uf, ni idea, no lo vi.
Hey, who won the game last night? — Ugh, no idea, I didn't watch it.
Señor, ¿podría confirmarme la hora de llegada del vuelo 305? — No sabría decirle, pero puedo verificarlo en el sistema.
Sir, could you confirm the arrival time for flight 305? — I wouldn't be able to tell you, but I can check it in the system.
¿Estás seguro de que esta es la dirección correcta? — La verdad, no estoy muy seguro. El GPS dice que sí.
Are you sure this is the right address? — Honestly, I'm not very sure. The GPS says it is.
🌍Cultural Context
The Art of Softening 'No Sé'
While 'No sé' is perfectly correct, Spanish speakers often soften this direct statement in conversation to sound more friendly. They might add words like 'Pues...' (Well...), 'La verdad...' (To be honest...), or a polite 'Lo siento' (I'm sorry) before it. This makes the response feel less blunt and more collaborative.
'Quién Sabe' and a Relaxed View of Time
In many parts of Latin America, the phrase 'Quién sabe' reflects a more fluid and relaxed cultural attitude towards schedules and future events. It's not just 'I don't know,' but often implies 'It's out of my hands, and we'll see what happens.' This can be a big cultural difference from the strict scheduling common in many English-speaking countries.
Offering Help Instead of Saying No
In professional or service settings, it's often considered more polite to avoid a simple 'No sé.' A better response is to acknowledge you don't know and immediately offer a solution, like 'No estoy seguro, pero déjeme preguntar' (I'm not sure, but let me ask) or 'Voy a averiguarlo' (I'm going to find out).
Don't Forget the Shrug!
Body language is key! Saying 'No sé' or 'Ni idea' is almost always accompanied by a shoulder shrug, sometimes with upturned palms. This gesture is universal and instantly communicates your meaning, even if your pronunciation isn't perfect.
❌ Common Pitfalls
Using 'Yo No Sé' All the Time
Mistake: "Yo no sé dónde está el baño."
Correction: No sé dónde está el baño.
Confusing 'Saber' and 'Conocer'
Mistake: "To say 'I don't know that person,' a learner might say 'No sé esa persona.'"
Correction: No conozco a esa persona.
Wrong Verb Form: 'No Sabe'
Mistake: "A learner wanting to say 'I don't know' might say 'No sabe.'"
Correction: No sé.
💡Pro Tips
Match the Formality
Pay attention to your audience. Use the casual 'Ni idea' with friends your age. Stick to the more neutral 'No sé' or the polite 'No sabría decirle' with strangers, elders, or in professional settings. Using the wrong level of formality can sound awkward or even disrespectful.
Combine with a Question
To keep the conversation going, you can follow 'No sé' with a question. For example, 'No sé, ¿tú sabes?' (I don't know, do you know?) or 'No sé, ¿dónde podemos buscar?' (I don't know, where can we look?). This shows you're still engaged in the conversation.
Use 'No estoy seguro/a' to be Less Direct
If you feel 'No sé' is too blunt, 'No estoy seguro/a' (I'm not sure) is your best friend. It's a versatile phrase that works everywhere and shows hesitation rather than a complete lack of knowledge, which can feel softer and more polite.
🗺️Regional Variations
Spain
The expression 'A saber' is a hallmark of Spanish casual speech, used exactly like 'Who knows?' It's less common in Latin America. You'll also hear the informal plural 'No sabéis' when talking to a group of friends.
Mexico
'Quién sabe' is extremely common in daily conversation. The unique idiom 'Sepa la bola' is a very informal, historical phrase meaning 'nobody knows,' referencing the chaos of the Mexican Revolution. It's charming and very Mexican.
Argentina
'Ni idea' is used constantly in casual speech, often preceded by 'che.' The phrase 'Qué sé yo' is also very typical, used like 'What do I know?' to express uncertainty or dismissiveness. 'Andá a saber' is the local equivalent of 'Quién sabe.'
Caribbean (e.g., Cuba, Puerto Rico, Dominican Republic)
The speed and dropped consonants are the most defining features. Understanding the context is key because the sounds can be less distinct than in other regions. Politeness is often shown through tone of voice rather than specific formal phrases.
📱Texting & Social Media
No sé
Widely used in WhatsApp, Messenger, and other informal chat platforms for quick replies.
¿Vienes a la fiesta? - ns, tengo que ver
Are you coming to the party? - idk, I have to see
Ni puta idea
Used among close friends in very informal chats. It's the equivalent of the English 'no f***ing idea.' Do NOT use this in polite company.
¿Dónde dejé mis llaves? - npi
Where did I leave my keys? - nfi
💬What Comes Next?
You tell someone you don't know the answer to their question.
Bueno, gracias de todos modos.
Well, thanks anyway.
De nada. / No hay de qué.
You're welcome. / Don't mention it.
You say 'I'm not sure' in a professional context.
¿Podrías averiguarlo, por favor?
Could you find out, please?
Claro, lo investigo y te aviso.
Of course, I'll look into it and let you know.
You say 'Ni idea' to a friend.
¡Jaja, yo tampoco!
Haha, me neither!
A ver si alguien más sabe.
Let's see if someone else knows.
🧠Memory Tricks
This links the sound 'sé' to the English word 'say,' helping you remember that it's the phrase for when you can't say the answer.
🔄How It Differs from English
In English, saying a blunt 'I don't know' can sometimes sound dismissive or unhelpful. English speakers often add softeners like 'I'm sorry, but...' or 'I'm afraid I don't know.' While Spanish has polite alternatives, a simple 'No sé' is generally seen as a more neutral and direct statement of fact and isn't inherently rude.
The default phrase 'No sé' is more direct than the common softened phrases in English. Politeness in Spanish is often conveyed by offering to find the information or by using a slightly more elaborate phrase like 'No sabría decirle,' rather than by adding 'I'm sorry' before the basic statement.
False Friends & Common Confusions:
Why it's different: English uses 'to know' for both facts and familiarity. Spanish has two separate verbs: 'saber' for facts/information and 'conocer' for people/places/familiarity.
Use instead: For facts, use 'No sé la respuesta' (I don't know the answer). For people or places, use 'No conozco a Juan' (I don't know Juan) or 'No conozco Madrid' (I'm not familiar with Madrid).
🎯Your Learning Path
➡️ Learn Next:
How to say 'I don't understand'
This is another essential phrase for learners when you can't process what you've heard.
How to say 'Can you help me?'
After saying you don't know something, asking for help is a natural next step.
How to say 'I think so'
This is the positive counterpart to 'I'm not sure' and is used to express a less-than-certain opinion.
How to ask 'What does that mean?'
If you don't know the answer because you don't understand the question, this phrase is crucial.
✏️Test Your Knowledge
💡 Quick Quiz: I don't know
Question 1 of 4
You are at a new job and your boss asks you for a specific sales figure. What is the most appropriate and polite way to say you don't know?
Frequently Asked Questions
What's the real difference between 'No sé' and 'No lo sé'?
They are very similar and often used interchangeably. 'No sé' is a general 'I don't know.' 'No lo sé' specifically means 'I don't know *it*,' referring to a specific piece of information just mentioned. In practice, you can use 'No sé' for everything, but using 'No lo sé' in response to a direct question can make you sound slightly more precise.
Is it rude to just say 'No sé' in Spanish?
Generally, no. It's a direct statement of fact and isn't considered inherently rude. However, tone of voice matters a lot! To be safer in polite situations, you can soften it by saying 'Lo siento, no sé' (I'm sorry, I don't know) or use a gentler alternative like 'No estoy seguro/a' (I'm not sure).
How can I say 'I don't know' but also offer to help?
This is a great strategy, especially in professional settings! You can say, 'No sé, pero puedo averiguar' (I don't know, but I can find out) or 'No estoy seguro, déjame revisar' (I'm not sure, let me check). This shows you're helpful even if you don't have the answer immediately.
Can you remind me of the saber vs. conocer rule?
Absolutely! It's a tricky one. Use SABER for facts, information, and skills (how to do something). Think of it like 'knowing a fact.' Use CONOCER for people, places, and being familiar with things (like a book or a movie). Think of it as 'being acquainted with.'
What's a funny or slang way to say 'I don't know'?
Besides the super common 'Ni idea,' you might hear 'Me suena a chino' (It sounds like Chinese to me) when something is confusing. In Mexico, the slang 'Sepa la bola' is a fun, historical way to say 'Who knows?'. Be aware that many slang terms are very regional!
How do I say 'I don't know yet'?
That's a useful one! You would say 'Todavía no sé' or 'Aún no sé.' Both 'todavía' and 'aún' mean 'yet' or 'still' in this context. For example, '¿Vienes a la cena? - Todavía no sé.' (Are you coming to dinner? - I don't know yet.)
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