A0 · 11 · Complete beginner

When to Use No entiendo and No sé

When a conversation gets away from you, you do not have to switch straight to English. These short responses let you explain whether the words were unclear or you simply do not know the answer, so the conversation can continue.

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What you'll be able to do

✓Say that you do not understand without switching to English.
✓Distinguish between not understanding and not knowing the answer.
✓Respond naturally when you understand, do not know or have no idea.
✓Recognise informal questions asking whether you understand.

Two different problems

The important distinction is whether the message made sense. Use no entiendo when you have not understood the words or meaning. Use no sé or no lo sé when you understood the question but do not know the answer.

English speakers sometimes say “I don’t know” when they really mean “I didn’t follow that”. Spanish makes the problem clearer by distinguishing between not understanding and not knowing.

Situation	What to say	Meaning
The words or meaning are unclear	no entiendo	I don’t understand
Nothing made sense	no entiendo nada	I don’t understand anything / at all
The question is clear, but the information is missing	no sé / no lo sé	I don’t know
You want a deliberately informal answer	ni idea	No idea / not a clue

When the message is unclear

No entiendo means “I don’t understand”. Spanish places no directly before entiendo and does not add anything equivalent to the English word “do”. Remember the complete phrase together.

Use perdona, no entiendo to interrupt a friend or someone you address informally. Perdona makes the interruption polite and gives the other person a chance to explain more clearly.

No entiendo nada is stronger. It means that you understood nothing at all. Spanish naturally keeps both no and nada, although standard English says “I don’t understand anything” rather than “I don’t understand nothing”.

When you do not know

No sé is the short, neutral answer when the question is clear but you do not have the information. The written accent in sé is part of the word.

No lo sé is equally neutral. The word lo refers back to the information being discussed. English often leaves out “it” here, so both phrases normally become “I don’t know” in English.

Ni idea means “no idea” or “not a clue”. It is natural with friends and in casual conversation, but it can sound a little blunt with a stranger at a desk. Use no sé or no lo sé there.

Checking and confirming

¿Entiendes? asks whether you understand what is being said. ¿Me entiendes? asks whether you understand the speaker. Both are informal questions that you only need to recognise for now.

Tone matters. With a friendly tone, ¿Me entiendes? is an ordinary check. With a sharp tone, it can sound impatient.

If you have followed, answer entiendo. After someone has clarified something, vale, entiendo naturally means “OK, I’ve got it”.

The words

no entiendo: I don’t understandUse it when the words or meaning are unclear.
no entiendo nada: I don’t understand anything / I don’t understand at allA stronger response when nothing made sense.
perdona, no entiendo: excuse me, I don’t understandAn informal, polite way to interrupt someone.
entiendo: I understandUse it to confirm that the message makes sense.
no sé: I don’t knowA short, neutral answer when you lack the information.
no lo sé: I don’t knowAn equally neutral answer in which lo refers to the information.
ni idea: no idea / not a clueInformal and natural with friends, but potentially blunt with a stranger.
¿entiendes?: do you understand?An informal question to recognise rather than produce.
¿me entiendes?: do you understand me?An informal question whose tone can sound friendly or impatient.

More examples: real moments

Outside the buildingOutside their block of flats in the morning, Carmen asks Javi where Lucía is.

Carmen: Buenos días, Javi. ¿Dónde está Lucía?Good morning, Javi. Where is Lucía?
Javi: Buenos días. Lo siento, no lo sé.Good morning. I’m sorry, I don’t know.
Carmen: Vale, gracias.OK, thanks.

A difficult phone callDuring an evening phone call with a poor connection, Lucía repeats her question to Javi.

Lucía: ¿Dónde está Carmen?Where is Carmen?
Javi: Perdona, no entiendo.Excuse me, I don’t understand.
Lucía: Carmen. ¿Dónde está Carmen?Carmen. Where is Carmen?
Javi: Ni idea.No idea.

Directions to the flatAt the entrance to Lucía’s block, she gives Nerea directions to her flat.

Lucía: Arriba, a la izquierda, al fondo.Upstairs, on the left, at the back.
Nerea: Perdona, no entiendo nada.Excuse me, I don’t understand anything.
Lucía: Arriba. A la izquierda. Al fondo. ¿Me entiendes?Upstairs. On the left. At the back. Do you understand me?
Nerea: Vale, entiendo. Muchas gracias.OK, I understand. Thank you very much.

Remember

•Use no entiendo when the words or meaning are unclear.
•Use no entiendo nada when nothing made sense.
•Use no sé or no lo sé when the question is clear but the answer is unknown.
•Use ni idea as an informal response with friends.
•Answer ¿entiendes? or ¿me entiendes? with entiendo when you have followed.

Practice

Type or choose your answer; each one is checked as you go.

1. Understanding or knowing?

Choose the response or meaning that fits each situation.

1.Someone gives you directions, but the words do not make sense. Which reply fits?
2.You understood the question, but you do not know where Carmen is. Choose the shortest neutral reply.
3.None of a long explanation made sense. What should you say?
4.A friend asks where Dani is. Choose the deliberately informal response.
5.What does ¿me entiendes? ask?

2. Complete the phrases

Fill each gap with one word.

1.Complete the stronger response: No entiendo .
2.Complete the longer neutral response: No sé.
3.You have followed the explanation now: Vale, .
4.You understood the question but do not know the answer. Complete the shortest neutral response: No .
5.Complete the informal response: Ni .

3. Say it in Spanish

Translate each short response into Spanish.

1.Translate into Spanish: I don’t understand at all.
2.Translate into Spanish using perdona: Excuse me, I don’t understand.
3.Translate into Spanish using the longer neutral response: I don’t know.
4.Translate into Spanish: OK, I understand.

4. Stay in the conversation

Write a natural reply for each situation.

1.During a phone call, you do not understand what was said. Give the shortest direct response from the page.
2.At a public desk, a stranger asks where Carmen is. Begin with lo siento, then say neutrally that you do not know.
3.A friend asks where Lucía is. Give the informal “no idea” response.
4.Someone explains the directions again and asks ¿entiendes?. Confirm that you have followed.

Your turn

Write three short Spanish responses, one for something you have not understood, one for a clear question whose answer you do not know, and one confirming that you understand. Then say all three aloud.

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Grammar in this lesson: Word stress and the written accent · Tú, usted, vosotros and ustedes · Asking questions · Saying no: negatives · Direct and indirect object pronouns

Revised 29 October 2026