What is the difference between Passato Prossimo and Imperfettto tenses in Italian?

Question

Both are used in the past tense.

Answer 1

Passato prossimo indicates a specific past action that has completed once.

i.e.

Ieri sera ho mangiato una pizza alle 23:00.

(Last night I ate a pizza at 11:00pm.)

This action is now completed.

Imperfetto describes a past action that was ongoing and habitual.

This is introduced by:

Ogni

Di solito

Spesso

i.e.

Ogni anno andavo al mare

(Every year I went to the shore.)

Di solito, prendevo un caffe' al bar.

(Usually, I got a coffee at the bar)

Spesso leggevo per 2 due ore.

(Often, I read for 2 hours)

(The above past action that was ongoing)

Answer 2

To express a concluded action, use the past tense :

I've been out for 10 minutes - sono uscito da 10 minuti

To express a habitual past action - repeated, use the imperfect tense:

I usually left the house at 7.00 in the morning - di solito uscivo di casa alle 7.00 del mattino.

Answer 3

There is just one thing I'd like to add to Lou's perfect answer.

In English, we often use "would" or "used to" to express what Italian means by using 'Imperfetto', e.g.:

Di solito, prendevo un caffè al bar.

(I always used to get a coffee at the bar./ I would always get a coffee at the bar.)

Or the other example:

Spesso leggevo per 2 due ore.

(I used to read a lot, often for two hours./ I would often read for 2 hours.)

It creates an often sentimental feeling of "back in the days, but I don't do this anymore".