To express possibility: Probably the most common use of "may" is to express possibility. In this way, the meaning is often roughly the same as the auxiliary verb "might." This can be translated in different ways, but typically the Spanish would require the uses of a verb in the subjunctive mood. Note how there is no single word in the following sample sentences that means "may." The sentence in parentheses following the Spanish translation is a literal translation of the Spanish and should have roughly the same meaning as the original English sentence.
- They may make a new version of the book. Es posible que hagan una nueva versión del libro. (It is possible that they will make a new version of the book.)
- She may be pregnant. Es posible que esté embarazada. (It is possible that she is pregnant.)
- There may be more than one for each person. Tal vez haya más de una para cada persona. (Perhaps there is more than one for each person.)
- We may go to New York to spend our honeymoon. Posiblemente vayamos a pasar nuestra luna de miel a Nueva York. (Possibly we will go to New York to spend our honeymoon.)
- There may be 50 million of us in 2015. Quizá seamos 50 millones en 2015. (Maybe we will be 50 million in 2015.)
- She may not leave. Puede que no salga. (It can be that she doesn't leave.)
To seek or grant permission: "May" is commonly used when seeking permission to perform such action, or when giving permission. Generally, the verb poder gets the idea across well:
- May I go to the concert tonight? ¿Puedo ir al concierto esta noche?
- Yes, you may go. Sí, puedes ir.
- May we get more information about our account? ¿Podemos obtener otra información sobre nuestra cuenta?
- If you have any questions, you may call me. Si tienes preguntas, puedes llamarme.
Although in formal English speech a distinction is sometimes made between "may" and "can," there is no need to make such a distinction in Spanish, as poder functions for both meanings.
To express a desire: Although not especially common, "may" can be used to express a wish or desire. Sentences with that usage typically can be translated to a sentence beginning with que followed by a verb in the subjunctive mood:
- May he rest in peace. Que en paz descanse.
- May you live for many more years. Que vivas muchos años más.
- Be that as it may. Aunque así sea.
- Come what may. Pase lo que pase.
- Devil-may-care attitude. Actitud arriesgada/temeraria.
- May I help you? ¿En qué puedo servirle?
- We may as well study. Más vale que estudiemos.

