Gerund

1. -AR –> -ANDO

e.g. hablar –>hablando

2. -ER/-IR –> -IENDO

e.g. comer –> comiendo
e.g. vivir –> viviendo

3. IR verb with E->I or E->IE in present indicative –> E->I

e.g. sentir (present indicative: yo siento) –> sintiendo
e.g. pedir (present indicative: yo pido) –> pidiendo

4. IR verb with O->UE in present indicative –> O->U

e.g. dormir (present indicative: yo duermo) –> durmiendo

5. ER or IR verb with stem that ends in vowel, -ER/-IR –> -YENDO

e.g. creer –> creyendo

6. ER or IR verb with stem that ends in Ñ or LL, then -ER/-IR –> -ENDO

e.g. gruñir –> gruñendo
e.g. zambullir –> zambullendo

gerund in Spanish ≈ gerund in English

1. Used in all the progressive forms

e.g. Estoy bailando. -> I am dancing.

2. With other verbs or without verbs

e.g. Sigues hablando. -> You keep talking.
e.g. Miro el mar, esperando ver algo. -> I watch the sea, hoping to see something.