When you are directly addressing a person or persons that you would normally address as usted or ustedes, give formal commands by taking the yo form of the present indicative tense and changing the ending of -ar verbs to -e for singular (usted) commands or -en for plural (ustedes) commands and changing the ending of -er/-ir verbs to -a or -an. Because you are working from the yo form of the present indicative, the formal commands reflect the irregularities you find in irregular and stem-changing verbs.

Regular Verbs

-AR
 

-ER/-IR
 

Verbs with Irregular yo Forms
 

Stem-Changing Verbs
 

*NOTE: A spelling change is necessary to preserve the sound of the infinitives that end in -car, -gar, and -zar: c > qu, g > gu, and z > c.

A few verbs have irregular command forms and must be memorized: