How to Say “I Know” in Spanish: Formal and Informal Ways

Welcome to our comprehensive guide on expressing “I know” in Spanish, covering both formal and informal ways. Understanding how to convey this common phrase is essential for effective communication in any language. In Spanish, there are several ways to express “I know” depending on the context and level of formality. So, let’s dive right in and explore the different ways to convey this expression effectively.

1. Formal Ways to Say “I Know” in Spanish

When engaging in a formal or professional setting, it is important to use the appropriate level of formality in your speech. Here are some phrases you can use to convey “I know” in Spanish formally:

a) “Sé”

The most common way to say “I know” formally in Spanish is by using the verb “saber.” It is conjugated as “sé” in the first-person singular present tense. Here are some examples:

1. Sé que el informe está listo.
(I know that the report is ready.)

2. Sé cómo resolver este problema.
(I know how to solve this problem.)

3. Sé que has trabajado duro.
(I know you have worked hard.)

Remember to use “sé” only when you are certain about the knowledge you possess.

b) “Tengo conocimiento de”

Another formal way to express “I know” in Spanish is by using the phrase “tengo conocimiento de.” This phrase implies a higher degree of formality and is often used in professional settings. Consider the following examples:

1. Tengo conocimiento del nuevo procedimiento.
(I have knowledge of the new procedure.)

2. Tengo conocimiento de sus habilidades.
(I am aware of your skills.)

Using this phrase portrays you as knowledgeable and professional in your communication.

2. Informal Ways to Say “I Know” in Spanish

In less formal situations, such as conversations with friends, family, or informal settings, you can use the following expressions to convey “I know” in a more relaxed tone:

a) “Lo sé”

The most common way to say “I know” informally in Spanish is by simply using the phrase “lo sé.” Here, the pronoun “lo” refers to the fact or piece of information you know. Take a look at the following examples:

1. Lo sé, pero quiero probarlo de todos modos.
(I know, but I want to try it anyway.)

2. Lo sé, gracias por recordármelo.
(I know, thanks for reminding me.)

b) “Ya sé”

Another informal way to say “I know” in Spanish, mostly used in Latin America and certain regions, is by using the phrase “ya sé.” This expression implies a sense of “I already know.” Let’s see some examples:

1. Ya sé que llegará tarde.
(I know he/she will arrive late.)

2. Ya sé cómo hacerlo.
(I know how to do it.)

Using “ya sé” conveys a sense of familiarity and often implies that the information is not new to you.

Additional Tips for Expressing “I Know” in Spanish

To further enhance your understanding of expressing “I know” in Spanish, consider the following tips:

Maintain Cultural Sensitivity

Language is closely tied to culture, so it is crucial to remain sensitive to the cultural nuances when using Spanish. Be aware that regional variations may exist, and certain phrases may be more prevalent in specific countries or communities. Keeping this in mind will help you navigate conversations more effectively.

Non-Verbal Communication

Remember that non-verbal cues, such as facial expressions and gestures, play an important role in communication. While learning the phrases for “I know” in Spanish is essential, paying attention to non-verbal signals will facilitate better understanding and strengthen your connections with Spanish speakers.

Practice and Immersion

Learning a new language takes time and practice. Immerse yourself in the Spanish language as much as possible by watching movies, listening to music, and engaging in conversations with native speakers. Consistent practice and exposure will help you become more proficient in expressing yourself, including saying “I know” confidently.


By now, you have gained valuable insights into expressing “I know” in Spanish, both formally and informally. Remember to adapt your language based on the level of formality required in different situations. Whether it’s using “sé” in formal contexts or “lo sé” in casual conversations, learning to express “I know” effectively will enhance your ability to communicate in Spanish.

Keep practicing, stay immersed, and embrace the cultural aspects of the Spanish language. ¡Buena suerte! (Good luck!)

Written by Katherine Alisha

Hola, I'm Katherine, your friendly language enthusiast! My passion for Spanish has led me to pen practical guides on diverse phrases - from saying "Iced coffee" to expressing "Zero fear". When not spinning the magic of words, you'll find me enjoying a thrilling game of dominoes or immersing in the intriguing world of tarot cards. Be it playful slang or formal language, I cover it all. Stick with me, and I'll help you navigate the beautiful maze of Spanish. ¡Estoy aqui para ayudarte!

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