Spanish has two verbs for "to know" — saber and conocer — and picking the wrong one is one of the most common mistakes English speakers make. The rule, though, is refreshingly clear once you see it.

The core difference in one line

Saber = to know facts, information, or how to do something.
Conocer = to be familiar with people, places, or things.

When to use SABER

  • Facts and information: Sé tu número de teléfono. (I know your phone number.)
  • Knowing that / knowing where / knowing why: Sé que vives en Madrid. (I know that you live in Madrid.)
  • Knowing how to do something (saber + infinitive): Sé nadar. (I know how to swim.) — no word for "how" is needed.

When to use CONOCER

  • People: Conozco a Juan. (I know Juan.) — note the personal a.
  • Places: Conozco Madrid muy bien. (I know Madrid well.)
  • Being familiar with a thing or subject: Conozco esa canción. (I know that song.)

A quick test: if you could replace "know" with "am familiar with" or "have met/been to", use conocer. If you could replace it with "know a fact" or "know how", use saber.

Both are irregular in the "yo" form

This trips people up in the present tense:

  • saber → sé, sabes, sabe, sabemos, sabéis, saben
  • conocer → conozco, conoces, conoce, conocemos, conocéis, conocen

Only the first person is odd; the rest are regular.

The twist: they change meaning in the past

In the preterite (completed past) both verbs shift meaning in a way worth memorising:

  • supe = I found out / I learned (a fact) → Supe la verdad ayer.
  • conocí = I met (for the first time) → Conocí a mi novia en Madrid.

So conocí a Ana means "I met Ana", not "I knew Ana". For the ongoing "I used to know", you'd use the imperfect: conocía, sabía.

Frequently Asked Questions

How do I remember which is which?

Think: saber = facts & skills, conocer = people & places. If "am familiar with" fits, it's conocer. If "know that / know how" fits, it's saber.

Why is it "sé" with an accent?

The accent distinguishes sé (I know) from se (the reflexive pronoun). They sound the same, so the written accent keeps them apart.

Do I need the personal "a" with conocer?

Yes, when you know a person: Conozco a María. With places or things there is no personal a: Conozco Madrid.

Can I say "sé a Juan"?

No. People are always conocer: Conozco a Juan. Use saber for facts about Juan: Sé dónde vive Juan.

The saber/conocer split becomes automatic with practice. On a free trial lesson a native teacher corrects it in real time. See also ser vs estar and present-tense conjugation.