Spazio vs. posto
While both spazio and posto can be translated into English as space or room, they represent different concepts of area. The word spazio refers to a general physical area, volume, or dimensions. On the other hand, the word posto refers to a specific spot, a seat, or a designated location available for a person or an object.
Spazio
The word spazio is used to describe a general physical area, volume, capacity, or abstract room. It focuses on the physical dimensions or the emptiness of an area rather than a specific designated spot.
C'è molto spazio in questo nuovo appartamento.
(There is a lot of space in this new apartment.)
Questo tavolo occupa troppo spazio in soggiorno.
(This table takes up too much room in the living room.)
Non ho abbastanza spazio sul disco rigido per salvare il video.
(I do not have enough space on the hard drive to save the video.)
Dobbiamo fare spazio per il nuovo armadio.
(We need to make room for the new wardrobe.)
Lascia uno spazio vuoto tra una riga e l'altra.
(Leave an empty space between one line and another.)
A volte ho solo bisogno di spazio per pensare in pace.
(Sometimes I just need space to think in peace.)
Posto
The word posto is used to describe a specific spot, a seat, or a designated location for an individual or an object. When translated as room, it implies having the exact availability, a slot, or an accommodation for someone or something to fit into.
C'è posto per un'altra persona in macchina?
(Is there room for another person in the car?)
Purtroppo non c'è più posto a sedere in questo treno.
(Unfortunately there is no more room to sit on this train.)
Ho tenuto un posto libero per te al tavolo.
(I saved a free spot for you at the table.)
Rimetti immediatamente quel libro al suo posto.
(Put that book back in its place immediately.)
Facciamo posto alle signore che stanno entrando.
(Let's make room for the ladies who are coming in.)
Troveremo un posto nel bagagliaio per la tua valigia.
(We will find a spot in the trunk for your suitcase.)
Summary
In short, use spazio when you are talking about general area, volume, or physical dimensions. Use posto when you are referring to a specific seat, a designated spot, or the exact room required to fit a particular person or item.