A regular-sized bedroom of approx. 350 sq ft will usually require two gallons of paint for the walls, one gallon for the ceiling, and one gallon for the trims and doors. If the color on the walls is dark and the color to be use is light, using a primer first as a base coat will provide better coverage. If primer is needed, two gallons will be needed. (The number of gallons estimated here will be enough to apply up to two coats).

A regular-sized bathroom of approx. 200 sq ft will usually require one gallon of paint for the walls, one gallon for the ceiling, and one gallon for the trims and doors. 

If the color on the walls is dark and the color to be use is light, using a primer first as a base coat will provide better coverage. If primer is needed, one gallon will be needed. (The number of gallons estimated here will be enough to apply up to two coats).

Other areas inside the house will usually be different from one house to another, areas such as the living room, dining room, entranceway hallways, stairways, and kitchens will usually need the same amount of paint as a regular bedroom, but in some cases, there will be spaces with different sizes and in order for us to provide a more accurate quantity we will need to take a look at it, something that we will be happy to assist you with.