A standard walk-in closet has dimensions of 7 feet by 10 feet at a minimum and an average of 100 square feet. Remember that the dimensions of the closet aren’t necessarily the usable space. This means that a 100-square-foot walk-in closet with shelves on each wall and an island may only have a walkable area of 50 square feet or less. Make sure you consider the effect of additions when you plan the room—mockups are a great idea.

The differences between a built-in closet and a walk-in aren’t that different from a built-in wardrobe and a walk-in closet. It’s fairly simple—a walk-in closet is a closet you can physically enter, stand in, and walk around in. A built-in (whether wardrobe or closet) is more akin to covered shelves installed into a recess in the wall. Another big difference is walk-in closets almost always have traditional full-size doors, while built-ins either have no doors or use sliding doors.

Different types of closets are defined mostly by size. A few different types of closets include:

• A reach-in closet is a smaller closet that you can stand in front of and reach everything inside it. Aside from the size, the doors and the level of drywall finish are typically the largest price factors.  

• A walk-in closet can be anything from a small 5-by-5 feet closet that has a narrow walkway with shelves on both sides to a 100 square foot bedroom-sized closet with shelving along the walls and plenty of room to move around in.

• A built-in wardrobe often does not have a door and leaves the clothes and other contents open to the room, whereas a closet usually has a door to separate it from the rest of the room.

Yes, adding a built-in or custom closet generally increases your home's value and makes it more attractive to potential buyers. A well-designed closet adds utility, organization, and a touch of luxury, which are appealing selling points. Most homeowners see a return on investment (ROI) of 50% to 60%; for example, a custom closet can add about $1,000 to your home's value on average. The specific ROI depends on the type, with custom walk-in closets typically providing more value than reach-in closets. However, to maximize value, ensure the closet doesn't significantly detract from the room's usable square footage. Converting an entire room into a closet can actually lower your home's value. Similarly, using overly lavish materials may not recoup their cost. A good strategy is to add a closet that takes square footage from a non-living area, such as a garage, to create a mudroom closet.