Room Size & Volume Calculator
The measurement everything else depends on. Enter dimensions once and get area, perimeter, volume and their metric equivalents.
- Perimeter
- 52 ft
- Volume
- 1485 cu ft
- Wall area
- 468 sq ft
- · Measure at floor level and again at waist height — older rooms are rarely square.
How to use the Room Size & Volume Calculator
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01
Measure the room length and width at floor level.
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02
Measure from the finished floor to the ceiling.
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03
Enter all three dimensions in feet, using decimals for inches.
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04
Use floor area for finishes, perimeter for trim, volume for ventilation, and wall area for decorating estimates.
Frequently asked questions
How do I enter inches?
Convert inches to a decimal of a foot: 6 inches is 0.5 feet and 3 inches is 0.25 feet.
What about an L-shaped room?
Split it into two rectangles, calculate each one, and add the results.
Does wall area subtract openings?
No. The wall area is gross. Subtract doors and windows when a product estimate requires it.
Other tools
Paint Calculator
Work out gallons of paint and primer for any room, including doors and windows.
Flooring Calculator
Boxes of flooring needed for any room, with a waste allowance for cuts and pattern.
Tile Calculator
Tiles, grout and adhesive for floors or walls, with breakage allowance.
Wallpaper Calculator
Rolls of wallpaper needed, accounting for pattern repeat.
These calculators give planning estimates based on the figures you enter. They are not a substitute for a site survey, a structural or load calculation, or professional advice. Always confirm quantities with your supplier or contractor before ordering.