Nominal mattress data
US labels on this site use common nominal dimensions: Twin 38 × 75, Twin XL 38 × 80, Full 54 × 75, Queen 60 × 80, King 76 × 80, and California King 72 × 84 inches. Actual products may vary, so user-entered measurements take priority.
Installed footprint
The planner adds the selected frame edge to both sides of the mattress width and to both ends of its length. When a manufacturer supplies overall width and length, those values are preferable to a uniform edge estimate.
Clearance calculation
For a rectangular room, left, right, head, and foot clearance are the room boundaries minus the placed frame coordinates. The displayed narrowest walking path uses active sides and does not account for unmodeled furniture or wall irregularities.
Fit language
We describe under 18 inches as generally impractical for an active path, 18–23 inches as tight, 24–29 inches as workable, and 30 inches or more as comfortable for many ordinary layouts. These editorial bands are not universal standards.
Units and rounding
One inch equals exactly 2.54 centimeters. Displayed values may be rounded, but fit calculations use the underlying numeric inputs. Recheck any result that depends on less than two inches of margin.