When do you use es?

Answer 1

Need more information to answer properly.

Is this question is asking when do you use the word "ES" (is) which is a form of the verb "Ser" as opposed to when do you use ESTA (is) which is a form of the verb "Estar"?

If so, there is a simple rule of thumb: If the the word is referring to something that is (or is considered) permanent, then you use the word "ES". If it is something transient, or impermanent, then you use the word "ESTÁ".

An example:

Él es enfermo

Él está enfermo

Both mean translate directly back to "he is sick". However the top one really means the person is ill either mentally or is not a well person, chronically ill. The bottom one means that the person is not feeling well or is just sick now and will bet better.

As with ANY rule of thumb, you have to watch out for the exceptions.

Está muerto (he's dead) seems to break the "permanence" rule. But if you dig deep into the language which is rooted in religion, death is transient. You move on to a life after death, so the impermanent verb is correct.

Es muerto (more properly "eres muerto") is a threat. That means "you're (a) dead (man)."

And then there is the occupation and marital status. In Spanish, those are permanent. Es un carpintero. (He is a carpenter) Es Casado (He is married). Though you can change your vocation and marital status the language considers these permanent. The use of "Está casado" is starting to take root in some areas, but the proper Spanish term would be ES, not Está.

When it comes to mood, if some one is a grumpy person, you would use the permanent state. If some one is just grumpy now and they are generally not that way, then you would use the transient term.

Answer 2

The Spanish word "es" is used as the third person singular form of the verb "ser," which means "to be." It is used to describe or define something in the present tense.