The recommended space for guest or secondary bedrooms is 10-by-12 feet, but you may wish for more in a master bedroom depending on what amenities you plan to include. Anything smaller than 9-by-11 feet will likely feel cramped.
Include 4 feet of clearance in front of closets to provide plenty of room to get dressed.
Straight closets should be no deeper than 24 inches.
Mark beds to scale with your plan to determine if there will be enough walkway space (30 inches minimum between furniture pieces) around your bed. See standard mattress sizes below.