The best place to start estimating the home size your need is your current rental. Most people would look to exceed the size of their current rental when buying a house.
Square footage
So almost all the time, a 1000sq ft house will be larger than a 1000sq ft apartment. But using the given size of your apartment is a good enough place to start filtering houses.
Bathrooms
Bathrooms consist of 4 factors:
If a bathroom has all 4 of them, it is considered a ‘full bath’. If it has 2 of those, it's a half-bath and so on.
A 3/4th bathroom is usually missing a tub. But not all 1/2 baths are the same, depending on which fixtures are part of it. 🤷
Bedrooms:
A room that can be classified as a bedroom needs to have a closable door and in-wall storage space (typically a closet)
So a 2 bedroom home may have more rooms that do not qualify as bedrooms.