What to say in Spanish when you want to ask how someone knows something

Introduction

Knowing how to ask how someone knows something in Spanish is a practical skill for conversations, interviews, and everyday curiosity. This article explains common phrases, variations for formality, verb choices, examples, and cultural notes so English-speaking learners can ask and respond naturally in Spanish.

Why ask how someone knows something?

In English we use phrases like how do you know or where did you hear that. In Spanish there are several ways to ask the same question depending on the context, politeness level, and whether you are questioning a claim, verifying information, or showing curiosity. Understanding the differences helps you sound more natural and avoid unintended rudeness.

Basic, direct ways to ask

The most straightforward way to ask how someone knows something is with a verb for knowing or hearing. Start with these simple, commonly used phrases.

Using the verb saber

Saber means to know facts or information. To ask how someone knows a fact, use:

¿Cómo sabes eso?
How do you know that?

Usage note: Use ¿Cómo sabe eso? for formal situations or when addressing someone with usted.

Using the verb oír

Oír means to hear. If the information was heard from someone else or from the news, ask:

¿De dónde oíste eso?
Where did you hear that?

Usage note: For usted, say ¿De dónde oyó eso?. For plural, use ¿De dónde oyeron eso?.

Using the verb enterarse

Enterarse means to find out or learn about something (often unexpectedly). Ask:

¿Cómo te enteraste de eso?
How did you find out about that?

Usage note: This phrase often implies that the information was not previously known by the speaker and may carry surprise.

Polite and formal variations

When speaking with strangers, older people, or in professional settings, choose a more polite structure. Use usted or conditional constructions to soften the question.

Formal with saber

¿Cómo sabe usted eso?
How do you know that? (formal)

Softening with ¿Podría decirme…?

To be especially polite, you can begin with ¿Podría decirme…?>, which means could you tell me. Combine it with one of the verbs:

¿Podría decirme cómo sabe usted eso?
Could you tell me how you know that?

Using indirect questions for politeness

Indirect questions sound less confrontational. For example:

Me gustaría saber cómo lo supo usted.
I would like to know how you came to know it. (formal)

Usage note: Lo supo uses the preterite of saber when referring to when someone found out.

Asking about sources and evidence

Sometimes you want to know the source, such as a person, website, or report. Use these phrases to ask where the information came from or who provided it.

Asking for the source

¿De dónde sacas esa información?
Where do you get that information from?

Usage note: Use ¿De dónde saca esa información? for usted and ¿De dónde sacan para ustedes/ustedes plural.

Asking who told them

¿Quién te dijo eso?
Who told you that?

Alternative: ¿Quién le dijo eso? (formal)

Asking about a specific source: media, social networks, friends

¿Lo viste en las noticias, en internet o te lo contó un amigo?
Did you see it on the news, online, or did a friend tell you?

Usage note: Use viste for informal tú; use vio for usted.

Questioning the claim: polite skepticism

If you doubt the information, there are ways to ask that express skepticism without sounding rude. Tone and context matter a lot in Spanish—choose softer verbs or conditional phrasing.

Soft skepticism with ¿En serio?

Start with ¿En serio? to show surprise, then follow with one of the question forms:

¿En serio? ¿Cómo lo sabes?
Seriously? How do you know that?

Using conditional and hypothetical language

To be gentle, frame the question as curiosity: ¿Me podrías explicar cómo lo supiste? or ¿Podrías decirme en qué basas esa información?.

Usage note: These forms are useful in professional or sensitive conversations where direct challenge may be inappropriate.

Asking about evidence and proof

When you need concrete proof, use vocabulary that requests evidence, documentation, or reasoning. This is common in academic, legal, or formal contexts.

Requesting evidence

¿Tienes alguna prueba o evidencia de eso?
Do you have any proof or evidence of that?

Asking for documentation

¿Puedes mostrarme el documento o la fuente?
Can you show me the document or source?

Asking for explanation of reasoning

¿En qué te basas para decir eso?
On what do you base that statement?

Usage note: This phrase is direct and often used in debates or analytical conversations.

Colloquial and regional expressions

Spanish varies by country. Below are casual, native-like phrases you might hear among friends or online.

Mexican and Central American expressions

¿Cómo sabes eso, güey? (informal, very casual)
How do you know that, dude?
Usage note: Güey is slang and can be offensive if used improperly—reserve it for close friends.

Spain and other regions

¿De dónde te has enterado?
Where did you find out about it?
Usage note: The present perfect te has enterado is common in Spain for recent events.

Latin American casual

¿Quién te contó eso? or ¿De quién lo supiste?
Who told you that? / Who did you hear it from?

Short dialogues with translations

Short dialogues help you see the phrases in context. Below are brief, natural exchanges for common situations.

At a party:
A: ¿Cómo supiste que veníamos?
B: Me lo dijo Laura.

At work verifying info:
A: ¿De dónde sacaste ese dato?
B: Lo encontré en el informe mensual.

Hearing a rumor:
A: ¿En serio? ¿Cómo te enteraste de eso?
B: Lo escuché en la radio esta mañana.

Verb conjugation quick reference

Here are key conjugations you will commonly use when asking how someone knows something. Remember to change the form for tú, usted, and plural subjects.

Saber: yo sé, tú sabes, él/ella/usted sabe, nosotros sabemos, vosotros sabéis, ellos/ustedes saben.
Use ¿Cómo sabes eso? for informal, ¿Cómo sabe usted eso? for formal.

Enterarse (pronominal): yo me enteré, tú te enteraste, él/ella/usted se enteró, nosotros nos enteramos.
Use ¿Cómo te enteraste de eso? for informal, ¿Cómo se enteró usted de eso? for formal.

Oír: yo oigo, tú oyes, él/ella/usted oye, nosotros oímos, ellos oyen.
Use ¿De dónde oíste eso? for informal, ¿De dónde oyó eso? for formal.

Common follow-up questions

After asking how someone knows something, these follow-ups are useful to get more detail or verify accuracy.

¿Quién te lo dijo?
Who told you?

¿Cuándo te enteraste?
When did you find out?

¿Puedes compartir la fuente?
Can you share the source?

¿Es fiable esa fuente?
Is that source reliable?

Usage notes and cultural tips

Tone matters in Spanish. A direct ¿Cómo sabes eso? can sound accusatory in some contexts, so consider softening with ¿Podrías decirme…? or starting with ¿En serio? to express surprise. In many Spanish-speaking cultures, asking for proof can be sensitive, so be polite and avoid implying dishonesty unless necessary.

When addressing older adults or people in authority, prefer usted forms. In written Spanish, the present perfect is more common in Spain for recent events, while the simple past is frequent in Latin America.

Practice phrases to memorize

Memorize these high-frequency lines to use in real conversations:

¿Cómo lo sabes?
¿De dónde oíste eso?
¿Cómo te enteraste de eso?
¿Quién te dijo eso?
¿En qué te bases? (On what do you base it?)

Conclusion

Asking how someone knows something in Spanish involves a handful of verbs and options that change with formality and context. Use saber, enterarse, and oír for most situations; soften questions with polite phrasing; and pick regional expressions carefully. With the example phrases and cultural tips above, you can ask naturally and confidently in Spanish.