Square Footage Calculator

Calculate the area of any space in square feet, meters, or yards — for flooring, painting, landscaping, and construction projects.

Reference table

Length	Area	Area (Metric)	Area (Yards)
0.5	5 sq ft	0.46 m²	0.56 sq yd
1	10 sq ft	0.93 m²	1.11 sq yd
1.5	15 sq ft	1.39 m²	1.67 sq yd
2	20 sq ft	1.86 m²	2.22 sq yd
2.5	25 sq ft	2.32 m²	2.78 sq yd
3	30 sq ft	2.79 m²	3.33 sq yd
4	40 sq ft	3.72 m²	4.44 sq yd
5	50 sq ft	4.65 m²	5.56 sq yd
6	60 sq ft	5.57 m²	6.67 sq yd
7	70 sq ft	6.5 m²	7.78 sq yd
8	80 sq ft	7.43 m²	8.89 sq yd
9	90 sq ft	8.36 m²	10 sq yd
10	100 sq ft	9.29 m²	11.11 sq yd
12	120 sq ft	11.15 m²	13.33 sq yd
15	150 sq ft	13.94 m²	16.67 sq yd

💡 Measurement Tips

Always measure twice and calculate once — small errors multiply with material purchases.
Add 10-15% waste for flooring (cuts, breakage). Use 5% for paint. Use 15-20% for diagonal or herringbone patterns.
For irregular rooms, break the space into simple shapes, calculate each, then add them together.
1 gallon of paint covers approximately 350-400 sq ft. Round up when ordering.

What Is Square Footage?

Square footage (sq ft) is a measurement of area — the amount of two-dimensional space a surface occupies. It's calculated by multiplying length by width when both are measured in feet. Square footage is the standard unit for measuring rooms, homes, and properties in the United States, Canada, and the United Kingdom. Whether you're buying flooring, estimating paint, pricing real estate, or planning a garden, accurate square footage calculations are essential for budgeting and ordering the right amount of materials. One square foot equals a 12-inch by 12-inch square, or approximately 0.0929 square meters.

How to Measure Square Footage

To measure square footage, start by choosing the shape that best matches your space. For rectangular rooms, simply measure the length and width in feet, then multiply them together. For circles, measure the diameter and use the formula π × (diameter/2)². For triangles, measure the base and height, then calculate ½ × base × height. For complex or irregular spaces like L-shaped rooms, divide the area into simpler shapes (rectangles, triangles), calculate each section separately, and add the results. Always measure from wall to wall at floor level, and convert all measurements to the same unit before calculating. When ordering materials, add a waste factor (typically 10%) to account for cuts, breakage, and fitting.

Key Considerations

Rectangular areas use the simplest formula: Length × Width. Most rooms and standard spaces are rectangular.
For flooring, add 10% waste for straight layouts. Diagonal patterns need 15%, and herringbone needs 20%.
1 acre equals 43,560 square feet. 1 square yard equals 9 square feet. 1 square meter equals 10.764 square feet.
When measuring for paint, calculate wall area (height × width for each wall) and subtract windows and doors.
Real estate square footage typically includes only finished, heated/cooled living space — not garages, attics, or unfinished basements.
Always round up material orders — you can't buy partial boxes of tile or partial gallons of paint.

Common Area Formulas

Rectangle: Area = Length × Width. The most common calculation for rooms and standard spaces.
Circle: Area = π × r² (where r = diameter ÷ 2). Used for patios, pools, garden beds, and round features.
Triangle: Area = ½ × Base × Height. Common for gable walls, roof sections, and decorative spaces.
Trapezoid: Area = ½ × (Base₁ + Base₂) × Height. Used for cathedral walls and irregular lot shapes.
L-Shape: Calculate as a full rectangle minus the cutout rectangle. Common for kitchens and open floor plans.
Irregular shapes: Divide into simple shapes, calculate each, and add together. Always overestimate for materials.

Calculation Examples

Step-by-step square footage calculations

Bedroom Flooring (Rectangle)

Room dimensions: 12 ft × 10 ft
Area = 12 × 10 = 120 sq ft
With 10% waste: 120 × 1.10 = 132 sq ft
At $3.50/sq ft: 132 × $3.50 = $462

Order 132 sq ft of flooring — total cost: $462

Circular Patio (Circle)

Patio diameter: 16 ft → radius = 8 ft
Area = π × 8² = 3.14159 × 64 = 201.06 sq ft
With 15% waste: 201.06 × 1.15 = 231.22 sq ft
In square meters: 201.06 ÷ 10.764 = 18.68 m²

Patio area: 201.1 sq ft (18.7 m²) — order 232 sq ft of pavers

Frequently Asked Questions

How do I calculate the square footage of a room?

Measure the length and width of the room in feet, then multiply them together. For example, a room that is 12 feet long and 10 feet wide has an area of 120 square feet (12 × 10 = 120). For rooms that aren't perfect rectangles, break them into simpler shapes, calculate each section, and add the results.

How many square feet are in an acre?

One acre equals 43,560 square feet. To convert square feet to acres, divide by 43,560. For example, a 10,000 sq ft lot is approximately 0.23 acres. One hectare equals approximately 2.47 acres or 107,639 square feet.

How much waste factor should I add for materials?

For straight-lay flooring (hardwood, laminate, vinyl), add 10%. For diagonal layouts, add 15%. For herringbone or complex patterns, add 20%. For paint, 5% is usually sufficient. For tile, add 10-15% for cuts and breakage. Always round up to the nearest full box or gallon.

How do I convert between square feet and square meters?

To convert square feet to square meters, divide by 10.764. To convert square meters to square feet, multiply by 10.764. For example, 200 sq ft ÷ 10.764 = 18.58 m², and 50 m² × 10.764 = 538.2 sq ft.

How do I calculate the square footage of an L-shaped room?

Imagine the L as a full rectangle with a corner cut out. Calculate the full rectangle area (main length × main width), then subtract the cutout area (cutout length × cutout width). For example, a 20×15 room with an 8×6 cutout: (20 × 15) - (8 × 6) = 300 - 48 = 252 sq ft.

How much does flooring cost per square foot?

Flooring costs vary widely: vinyl/laminate runs $1-5/sq ft, hardwood $5-15/sq ft, tile $2-20/sq ft, and carpet $1-8/sq ft (materials only). Installation adds $2-8/sq ft depending on material and complexity. Always calculate total area with waste factor before getting quotes.