Room Size Calculator

Calculate room floor area, wall area, ceiling area, room volume, perimeter, and totals for multiple same-size rooms.

Use this Room Size Calculator to calculate floor area, wall area, ceiling area, perimeter, room volume, and totals for multiple rooms of the same size.

Room Size Formulas

Floor area = length × width

Perimeter = 2 × (length + width)

Wall area = perimeter × height

Ceiling area = length × width

Room volume = length × width × height

Total surface area = wall area + floor area + ceiling area

For multiple identical rooms, each result is multiplied by the number of rooms.

Example

Suppose a room is 12 ft long, 10 ft wide, and 8 ft high.

Floor area = 12 × 10 = 120 ft²

Perimeter = 2 × (12 + 10) = 44 ft

Wall area = 44 × 8 = 352 ft²

Room volume = 12 × 10 × 8 = 960 ft³

The room therefore has a floor and ceiling area of 120 ft², a wall area of 352 ft², and a volume of 960 ft³.

Important Note

The calculator assumes a simple rectangular room. For L-shaped rooms, alcoves, closets, sloped ceilings, or other irregular layouts, divide the space into simple sections, calculate each section separately, and add the results.

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