The mattress is not the bed.

US mattress sizes

The frame adds 2–5″ on each axis. A "queen bed" on a floor plan is not 60 × 80 — with a typical frame it's closer to 65 × 85, and a wingback headboard or a storage footboard adds more. Poché's bed stencils are mattress footprints with the frame noted; when you shop a real bed, the listing's outer frame dimensions are the numbers that matter.

The clearances a bedroom needs

• Bed sides: 24–30″ each — enough to walk, make the bed, and open a nightstand drawer. 36″ where a side doubles as the main path.
• Dresser front: 36″ — an open drawer is ~26″ of it, and you stand in the rest. Dressers run 48–72″ wide × 18–20″ deep.
• Nightstands: 18–32″ wide. Match height to the top of the mattress.
• Closet & door swings: a 30–36″ door sweeps a quarter-circle of its own width — furniture can't live in it.
• Murphy bed: a queen cabinet is only ≈65 × 16 closed — but needs ~87″ clear in front to fold down. Plan the open state.

Does a king fit in a 12 × 12 room?

Worked honestly: a king with frame is ≈80″ wide. A 12-foot wall is 144″. That leaves 64″ to split between the two sides — a comfortable 32″ each, if nothing else lives on those walls. Add a 20″-deep dresser on one side and its 36″ of standing room, and you're at 56″ committed — the bed must slide off-center, one side drops to the minimum, and the door swing decides whether it works at all. That's a lot of arithmetic for one corner of one room — which is why Poché just draws it on your plan and flags what pinches.