Square Footage Calculator

How to Use This Square Footage Calculator

Select the shape: Rectangle, Circle or Triangle
Enter the dimensions in your preferred unit (feet, meters, inches or yards)
Optionally add price per square foot for a cost estimate
Click Calculate Area to see results in sq ft, sq m and sq yd

Common Room Examples

Quick reference for typical room sizes (rectangle).

Room Size	Square Feet	Square Meters	Square Yards
10 × 12 ft	120 ft²	11.1 m²	13.3 yd²
12 × 15 ft	180 ft²	16.7 m²	20.0 yd²
15 × 20 ft	300 ft²	27.9 m²	33.3 yd²
20 × 20 ft	400 ft²	37.2 m²	44.4 yd²

For flooring or carpet, add 5–10% waste on top of these numbers.

Common Uses

Use Case	What to Measure
Flooring / Carpet	Room length × width
Paint / Wallpaper	Wall length × height (minus openings)
Land / Lawn	Property dimensions
Tile / Hardwood	Floor area + waste
Concrete Slab	Length × width

Formulas Used

Rectangle: Area = Length × Width

Circle: Area = π × (Diameter ÷ 2)²

Triangle: Area = (Base × Height) ÷ 2

Conversions: 1 m² ≈ 10.764 ft² | 1 yd² = 9 ft²

How to Calculate Square Footage

Square footage is one of the most common measurements in home improvement, real estate and construction. Accurate area calculations help you order the right amount of flooring, paint, tile or landscaping materials.

Rectangular Rooms

Most rooms are rectangular. Measure length and width in feet, then multiply. Example: a 12 ft × 10 ft room = 120 square feet.

Irregular Shapes

Break the space into rectangles, circles or triangles. Calculate each part separately and add the results together for the total area.

Walls for Paint

Measure the length of each wall and multiply by ceiling height. Subtract doors and windows for a more accurate paint estimate. One gallon of paint typically covers 350–400 sq ft.

Tips for Accurate Measurements

Use the same unit for all measurements before calculating.
Measure twice — small errors multiply on large areas.
Add waste — 5–10% extra is common for flooring, tile and carpet.
Account for openings when calculating wall area for paint or wallpaper.
Round up when ordering materials so you do not run short.

Frequently Asked Questions

How do I calculate square footage?

For a rectangle, multiply length by width. For a circle, use π × (radius)². For a triangle, use (base × height) ÷ 2. Convert all measurements to the same unit first (usually feet).

How many square feet are in a square meter?

1 square meter equals approximately 10.764 square feet. 1 square yard equals 9 square feet.

How do I calculate square footage of a room?

Measure the length and width of the room in feet, then multiply them together. For irregular rooms, break the space into rectangles or triangles and add the areas.

Should I add waste when calculating flooring square footage?

Yes. Add 5–10% extra for cuts, waste and pattern matching when ordering flooring, tile or carpet. This calculator shows the exact area; add waste on top as needed.

How do I calculate wall square footage for paint?

Measure the length of each wall and multiply by the height. Add all walls together, then subtract the area of doors and windows for a more accurate paint estimate.

What is the difference between square feet and square yards?

1 square yard = 9 square feet. Carpet and some outdoor materials are often sold by the square yard, while flooring and tile are usually sold by the square foot.

Can I use this for outdoor land area?

Yes. Measure the length and width of the lot or lawn area. For irregular shapes, divide into rectangles and triangles. Results are shown in square feet, square meters and square yards.

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