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Calculate room area in square feet, square meters, and square yards. Enter the length and width of any rectangular room to get instant, accurate results for flooring, painting, HVAC sizing, and more.
Area = Length × Width
The area of a rectangular room is found by multiplying the length by the width. Both measurements must be in the same unit. The result will be in square units (sq ft, sq m, or sq yd).
Below is a reference table of typical room sizes found in North American homes. These dimensions represent common ranges and may vary based on local building codes, architectural style, and home size.
| Room Type | Dimensions (ft) | Area (sq ft) | Area (sq m) | Typical Contents |
|---|---|---|---|---|
| Small Bedroom | 10 x 10 | 100 | 9.29 | Single bed, desk, small closet |
| Standard Bedroom | 11 x 12 | 132 | 12.26 | Double or queen bed, dresser, nightstand |
| Master Bedroom | 14 x 16 | 224 | 20.81 | King bed, walk-in closet, sitting area |
| Large Master Suite | 16 x 20 | 320 | 29.73 | King bed, ensuite bath, lounge area |
| Small Kitchen | 8 x 10 | 80 | 7.43 | Galley style, basic appliances |
| Standard Kitchen | 10 x 12 | 120 | 11.15 | L-shaped counter, island optional |
| Large Kitchen | 12 x 16 | 192 | 17.84 | Island, breakfast nook, double oven |
| Small Living Room | 12 x 12 | 144 | 13.38 | Sofa, TV stand, small coffee table |
| Standard Living Room | 12 x 18 | 216 | 20.07 | Sectional sofa, entertainment center |
| Large Living Room | 16 x 20 | 320 | 29.73 | Multiple seating areas, fireplace |
| Half Bathroom | 5 x 8 | 40 | 3.72 | Toilet, pedestal sink |
| Full Bathroom | 8 x 10 | 80 | 7.43 | Tub/shower, toilet, vanity |
| Master Bathroom | 10 x 14 | 140 | 13.01 | Double vanity, separate tub and shower |
| Home Office | 10 x 12 | 120 | 11.15 | Desk, bookshelf, filing cabinet |
| Dining Room | 12 x 14 | 168 | 15.61 | Table for 6-8, china cabinet |
| Laundry Room | 6 x 9 | 54 | 5.02 | Washer, dryer, folding counter |
| Single-Car Garage | 12 x 20 | 240 | 22.30 | One vehicle plus some storage |
| Two-Car Garage | 20 x 22 | 440 | 40.88 | Two vehicles plus workbench area |
Room size calculation is the process of determining the floor area of a room by measuring its length and width and multiplying these two dimensions together. The result is expressed in square units such as square feet (sq ft), square meters (sq m), or square yards (sq yd). This fundamental measurement is essential for virtually every aspect of home construction, renovation, and interior design.
For rectangular rooms, the calculation is straightforward: Area = Length × Width. A room measuring 12 feet long by 10 feet wide has an area of 120 square feet. For rooms measured in meters, the same formula applies, yielding square meters. When rooms are irregularly shaped, such as L-shaped or rooms with alcoves, you divide the space into multiple rectangles, calculate each area separately, and sum the results.
Understanding room size is critical for accurate material estimation. Whether you are purchasing flooring, calculating paint coverage, sizing an air conditioner, or planning furniture placement, knowing the exact square footage of your room prevents costly over-ordering or frustrating shortages. Real estate professionals also rely on accurate room measurements for property listings, appraisals, and compliance with building codes that specify minimum room sizes for habitable spaces.
Area (sq ft) = Length (ft) × Width (ft)
For metric: Area (sq m) = Length (m) × Width (m)
Using a tape measure, measure the longest dimension of the room from wall to wall. Record the measurement in feet and inches, or in meters.
Measure the perpendicular wall from side to side. Ensure you measure at floor level for the most accurate reading.
Multiply the two measurements together. The result is the room area in square units matching your measurement unit.
Multiply sq ft by 0.092903 for sq m, or divide sq ft by 9 for sq yd. Use our calculator above for instant conversions.
A bedroom measures 12 feet long and 11 feet wide.
Area = Length × Width
Area = 12 ft × 11 ft
Area = 132 sq ft
In sq m: 132 × 0.092903 = 12.26 sq m
In sq yd: 132 ÷ 9 = 14.67 sq yd
A living room measures 18 feet long and 14 feet wide.
Area = Length × Width
Area = 18 ft × 14 ft
Area = 252 sq ft
In sq m: 252 × 0.092903 = 23.41 sq m
In sq yd: 252 ÷ 9 = 28.00 sq yd
A kitchen measures 4.5 meters long and 3.5 meters wide.
Area = Length × Width
Area = 4.5 m × 3.5 m
Area = 15.75 sq m
In sq ft: 15.75 × 10.7639 = 169.53 sq ft
In sq yd: 169.53 ÷ 9 = 18.84 sq yd
To quickly estimate square meters from square feet, divide the square footage by 10 and then subtract about 7 percent. For example, 200 sq ft ÷ 10 = 20, then 20 - 1.4 = approximately 18.6 sq m (actual: 18.58 sq m).
| Length (ft) | Width (ft) | Area (sq ft) | Area (sq m) | Classification |
|---|---|---|---|---|
| 9 | 9 | 81 | 7.53 | Small / Child's Room |
| 10 | 10 | 100 | 9.29 | Guest Bedroom |
| 11 | 12 | 132 | 12.26 | Standard Bedroom |
| 12 | 14 | 168 | 15.61 | Large Bedroom |
| 14 | 16 | 224 | 20.81 | Master Bedroom |
| 16 | 20 | 320 | 29.73 | Master Suite |
| Room Type | Dimensions (ft) | Area (sq ft) | Area (sq yd) |
|---|---|---|---|
| Small Living Room | 12 x 12 | 144 | 16.00 |
| Medium Living Room | 14 x 16 | 224 | 24.89 |
| Large Living Room | 16 x 20 | 320 | 35.56 |
| Small Dining Room | 10 x 12 | 120 | 13.33 |
| Standard Dining Room | 12 x 14 | 168 | 18.67 |
| Large Dining Room | 14 x 18 | 252 | 28.00 |
| Room Type | Dimensions (ft) | Area (sq ft) | Area (sq m) |
|---|---|---|---|
| Small Kitchen | 8 x 10 | 80 | 7.43 |
| Standard Kitchen | 10 x 12 | 120 | 11.15 |
| Large Kitchen | 12 x 16 | 192 | 17.84 |
| Half Bathroom | 5 x 8 | 40 | 3.72 |
| Full Bathroom | 8 x 10 | 80 | 7.43 |
| Laundry Room | 6 x 9 | 54 | 5.02 |
| Home Office | 10 x 12 | 120 | 11.15 |
Accurate room measurements are essential for ordering the right amount of hardwood, tile, laminate, or carpet. Over-ordering wastes money, while under-ordering causes delays. Always add 10-15 percent extra for cuts and waste.
Knowing your room size helps calculate wall area for paint purchases. Multiply the room perimeter by ceiling height to find total wall area, then subtract doors and windows. One gallon covers approximately 350-400 square feet.
Room square footage directly determines the BTU capacity needed for heating and cooling. An undersized HVAC unit struggles to maintain temperature, while an oversized unit cycles too frequently and wastes energy.
Room dimensions determine what furniture fits comfortably. A standard sofa needs about 7-8 feet of wall space, and walkways should be at least 3 feet wide. Accurate measurements prevent purchasing furniture that is too large or too small.
Always take measurements at floor level. Walls can lean slightly, and baseboards can add thickness. Measuring at the floor gives the most accurate room dimensions for flooring and furniture placement.
Always double-check measurements before calculating. A small error of even one inch over a 20-foot wall compounds significantly when multiplied by the room width, leading to material over- or under-ordering.
A room that is 12 feet 6 inches long is 12.5 feet, not 12.6 feet. Convert inches to a decimal fraction of a foot by dividing by 12. For example, 6 inches ÷ 12 = 0.5 feet.
The calculated area is the net area. For materials like flooring, tile, and carpet, always add 10 percent for straight installations and 15 percent for diagonal patterns to account for cuts, waste, and matching.
Linear feet measure length only, while square feet measure area. A 12-foot board is 12 linear feet, but a 12 ft × 12 ft room is 144 square feet. These are different measurements used for different purposes.
When measuring total room area for flooring, include closet space and alcoves as separate rectangles. When measuring for furniture placement, use only the main room area excluding closets.
Multiply the room length by the room width. For example, a room that is 12 feet long and 10 feet wide has an area of 12 x 10 = 120 square feet. If your measurements are in inches, multiply length by width in inches and then divide by 144 to convert to square feet.
The average bedroom in the United States is approximately 132 square feet (about 11 x 12 feet). A master bedroom is typically larger at 200 to 350 square feet, while a small or guest bedroom may range from 70 to 100 square feet.
Multiply the area in square feet by 0.092903 to get square meters. For example, 200 square feet equals 200 x 0.092903 = 18.58 square meters. To convert the other way, multiply square meters by 10.7639 to get square feet.
A king-size bed measures approximately 76 x 80 inches (6.3 x 6.7 feet). For comfortable clearance around all sides, you need a minimum room size of about 12 x 12 feet (144 square feet), though 12 x 14 feet (168 square feet) or larger is recommended to accommodate nightstands and a dresser.
Break the room into smaller rectangular sections, calculate the area of each section separately by multiplying its length by its width, and then add all the areas together. For L-shaped rooms, divide the space into two rectangles. For rooms with alcoves, calculate the main rectangle and add the alcove area.
Calculate the total room area in square feet, then add 10 percent extra for waste from cuts and mistakes. For diagonal installations, add 15 percent. For example, a 200 square foot room needs about 220 square feet of flooring material (200 x 1.10 = 220).
Most building codes in the United States require habitable rooms to be at least 70 square feet with no dimension less than 7 feet. Kitchens must be at least 50 square feet. Bathrooms typically require a minimum of 35 to 40 square feet depending on local codes.
Calculate the room area in square feet and multiply by approximately 20 BTU per square foot for standard cooling. A 300 square foot room needs about 6,000 BTU (300 x 20). Adjust upward for sunny rooms, high ceilings, or kitchens, and downward for shaded rooms or mild climates.
One square yard equals 9 square feet. To convert square feet to square yards, divide by 9. For example, 180 square feet equals 20 square yards (180 / 9 = 20). Carpet is often sold by the square yard, so knowing this conversion is essential when shopping for flooring.
Calculate the wall area by multiplying the room perimeter by the ceiling height, then subtract the area of doors and windows. One gallon of paint typically covers 350 to 400 square feet. For a 12 x 12 foot room with 8-foot ceilings, the wall area is about 384 square feet, requiring approximately one gallon per coat.
This calculator is provided for informational and educational purposes only. Always verify measurements independently before purchasing materials or making construction decisions. UnitTables is not responsible for any errors, omissions, or outcomes resulting from the use of this tool.