Bed Size Calculator

Selecting a mattress without measuring guarantees one of two failures: a bed that cramps movement during sleep or one that blocks dresser drawers and closet doors. The clearance between a bed frame and the nearest wall must be at least 24in (61cm) for passage and 36in (91cm) for comfortable daily use. This calculator cross-references your room dimensions L_room × W_room, the number of sleepers, each sleeper's height h, and sleeping position preference against a database of 12 standard mattress sizes from US, UK, and EU markets. It computes a weighted comfort score S that penalizes insufficient length, inadequate per-sleeper width, and tight room clearances. The output is a ranked recommendation, not a guess.

Limitations: this tool assumes a rectangular room and does not account for angled walls, bay windows, or radiator placement. Frame overhang (typically 2 - 4in beyond mattress dimensions) is included as a configurable buffer. Pro tip: measure from baseboard to baseboard, not wall to wall, since baseboards can steal 0.5 - 1.5in per side.

The calculator computes a composite comfort score S for each candidate bed size. Four sub-scores are evaluated on a 0 - 100 scale and combined with empirical weights:

Where:

S_width measures per-sleeper width against a target of 30in (76cm) per person:

S_length ensures the mattress exceeds the tallest sleeper's height by at least 10in:

S_clearance evaluates minimum walkway space around the bed. The effective clearance is the smallest gap on any accessible side, compared against the 24in minimum:

S_ratio checks whether the bed consumes a reasonable share of floor area. The ideal range is 25 - 35% of room area:

Where W_bed = mattress width + frame buffer, L_bed = mattress length + frame buffer, n = number of sleepers, h_max = tallest sleeper height, C_min = minimum clearance on any accessible side, and R = bed-to-room area ratio. A score below 50 flags the size as unsuitable. Scores above 80 indicate an excellent fit.