It typically takes 4-6 months for a puppy to be fully house trained, but some puppies may take up to a year. Size can be a predictor. For instance, smaller breeds have smaller bladders and higher metabolisms and require more frequent trips outside. Your puppy's previous living conditions are another predictor. You may find that you need to help your puppy break old habits in order to establish more desirable ones.
Many owners appear disappointed that their young puppy will not toilet when out on a walk, yet relieves itself the second it gets back home. This is because the puppy has been taught to toilet only at home (hopefully in its garden), and being creatures of habit, they often wait until they have returned home before evacuating their bladder and/ or bowels.