How do I calculate square footage of a room?

For a rectangular room, multiply the length by the width in feet. For example, 12 ft × 10 ft = 120 sq ft. For irregular shapes, break the room into simpler geometric shapes (rectangles, triangles, circles), calculate the area of each, and add them together. This calculator supports rectangle, L-shape, triangle, and circle shapes and lets you combine multiple rooms.

How do I convert square feet to square meters?

Multiply square feet by 0.0929 to get square meters. For example, 500 sq ft × 0.0929 = 46.45 sq m. To convert the other direction, multiply square meters by 10.764 to get square feet. This calculator displays both units automatically.

How do I measure an irregularly shaped room?

Break the room into simple geometric shapes. For an L-shaped room, divide it into two rectangles, measure each, and add the areas. For rooms with angled walls, use triangles. For rooms with curved walls, approximate the curve as part of a circle. Use this calculator's "Add Room" feature to combine multiple sections into one total.

How many square feet is a 12x12 room?

A 12x12 room is 144 square feet (12 × 12 = 144). This is approximately 13.4 square meters, and is a common size for a standard bedroom or small living room.

What is the difference between gross and net square footage?

Gross square footage includes the total area within the building exterior walls, including walls, hallways, stairwells, and mechanical rooms. Net square footage (or usable area) is only the space you can actually occupy and use, excluding walls and common areas. Net is typically 80-90% of gross in commercial buildings. For residential properties, the Gross Living Area (GLA) is used, which includes finished, above-grade living space.

How do I calculate square footage for flooring?

Measure the length and width of each room at floor level. Multiply length by width for each room and add the areas together. Then add 5-10% extra for waste from cuts, mistakes, and future repairs. For tile, add 10-15% since more cuts are needed around edges and corners. Always round up when purchasing materials to avoid running short during installation.

Square Footage Calculator

Calculate the area of multiple rooms with different shapes and get the total in square feet and square meters.

Quick Answer

To calculate square footage of a rectangular room, multiply length in feet by width in feet: square footage = length x width. For a 12 ft by 15 ft room, that is 180 square feet. For irregular rooms, split the space into rectangles, calculate each, then add the totals. NIST defines 1 square meter as 10.7639 square feet.

Also searched as: square footage calculator, square footage, how to calculate square footage

Total Area

0 sq ft

0 sq m

How to Calculate Square Footage

Square footage is the standard unit of area measurement used in the United States for real estate, construction, flooring, landscaping, and home improvement projects. Knowing the precise square footage of a room, house, yard, or lot is essential for buying the right amount of materials, comparing property values, estimating project costs, and meeting building code requirements.

The most basic square footage calculation is for a rectangular space: simply multiply the length by the width, both measured in feet. A room that is 15 feet long and 12 feet wide has an area of 15 × 12 = 180 square feet. However, most real-world spaces are not perfect rectangles. Rooms may have alcoves, bay windows, closets, or irregular walls that require you to break the space into multiple simpler shapes, calculate each area separately, and add them together.

This calculator supports four common shapes -- rectangle, L-shape, triangle, and circle -- and lets you add multiple rooms to get the total area for an entire house, apartment, or commercial space. Results are displayed in both square feet and square meters for international convenience.

Square Footage Formulas by Shape

Shape	Formula	Example
Rectangle / Square	Length × Width	12 ft × 10 ft = 120 sq ft
Triangle	½ × Base × Height	½ × 10 ft × 8 ft = 40 sq ft
Circle	π × Radius²	π × 6² = 113.1 sq ft
Trapezoid	½ × (Base1 + Base2) × Height	½ × (8 + 12) × 6 = 60 sq ft
L-Shape	(L1 × W1) + (L2 × W2)	(12 × 10) + (8 × 6) = 168 sq ft

Key Terms

Term	Definition
Square Feet (sq ft)	The area of a square with sides of 1 foot. The standard unit for measuring floor area in the US.
Square Meters (sq m)	The metric equivalent of square feet. Used internationally and in scientific contexts. 1 sq m = 10.764 sq ft.
Linear Feet	A measurement of length only (not area). Used for baseboards, trim, and fencing. Do not confuse with square feet.
Lot Size	The total area of a parcel of land, usually expressed in square feet or acres.
Gross Area	Total area within the exterior walls of a building, including walls, hallways, stairwells, and mechanical rooms.
Net Area / Usable Area	The area you can actually occupy and use. Excludes walls, common corridors, and mechanical spaces. Typically 80-90% of gross area.
GLA (Gross Living Area)	The total finished, above-grade living area of a home. Used in real estate appraisals. Excludes basements, garages, and unfinished attics.

Area Conversion Table

From	To	Multiply By
Square Feet	Square Meters	0.0929
Square Meters	Square Feet	10.764
Square Feet	Square Yards	0.1111
Square Yards	Square Feet	9.0
Square Feet	Acres	0.0000229568
Acres	Square Feet	43,560

Practical Examples

Example 1: Measuring a Standard Bedroom

A rectangular bedroom measures 12 feet long and 11 feet wide. Square footage = 12 × 11 = 132 sq ft (12.26 sq m). If you are buying carpet, add 10% for waste: 132 × 1.10 = 145.2 sq ft. Since carpet is sold by the square yard, divide by 9: 145.2 / 9 = 16.1 square yards. Round up to 17 square yards to be safe.

Example 2: Irregularly Shaped Living Room

An L-shaped living room has a main section measuring 18 ft × 14 ft and a smaller nook measuring 8 ft × 6 ft. The total area is (18 × 14) + (8 × 6) = 252 + 48 = 300 sq ft (27.87 sq m). This method works for any room that can be divided into rectangles -- measure each section, calculate, and add.

Example 3: Calculating Whole House Square Footage

To find the total square footage of a house, measure each room individually and add the results. A typical layout might include: Master Bedroom (14 × 12 = 168 sq ft), Bedroom 2 (11 × 10 = 110 sq ft), Living Room (16 × 14 = 224 sq ft), Kitchen (12 × 10 = 120 sq ft), Bathrooms (2 × 48 = 96 sq ft), Hallways and closets (estimated 80 sq ft). Total = 798 sq ft. Note that official GLA (Gross Living Area) measurements for real estate include interior walls but exclude garages and unfinished basements.

Example 4: Yard and Lawn Measurement

A rectangular backyard measures 50 ft × 30 ft = 1,500 sq ft. To determine how much sod you need, subtract areas that will not be covered (patio: 12 × 10 = 120 sq ft, garden bed: 8 × 4 = 32 sq ft). Net lawn area = 1,500 − 120 − 32 = 1,348 sq ft. Most sod is sold in rolls covering about 10 sq ft each, so you would need approximately 135 rolls plus 5-10% extra.

Tips for Accurate Measurement

Measure at floor level: Walls are not always perfectly straight. Measure at the base where flooring will actually be installed for the most accurate results.
Use a laser distance measurer: For large rooms or long distances, a laser measurer is faster and more accurate than a tape measure. They typically cost $25-50 and are accurate to within 1/8 inch.
Record dimensions consistently: Always measure in the same units (feet and inches, or just feet with decimals). Convert inches to decimal feet by dividing by 12 (e.g., 10 ft 6 in = 10.5 ft).
Break complex rooms into simple shapes: Any irregular room can be divided into rectangles, triangles, or sections of circles. Measure each section, calculate its area, and add them together.
Include or exclude walls deliberately: For flooring, measure wall-to-wall. For furniture arrangement, measure the usable interior space. For real estate appraisals, measure from exterior walls.
Add a waste factor for materials: Add 5-10% for flooring, 10-15% for tile (more cuts needed), and 10-20% for paint on textured surfaces. Always round up when purchasing.
Double-check critical measurements: Measure each dimension twice and compare. For expensive projects like hardwood flooring or custom countertops, the cost of re-measuring is negligible compared to buying too much or too little material.
Account for closets and alcoves: Measure closets and alcoves separately and add them to the room total. For real estate listings, closets are typically included in room square footage.