About Area Calculator
Calculate area for rectangles, circles, triangles, trapezoids, and more. Free tool with instant results in sq ft, sq m, or sq yd — perfect for flooring and landscaping.
How to use
- Select the shape you want to calculate: rectangle, square, triangle, circle, trapezoid, parallelogram, or ellipse. Each shape requires different dimension inputs based on its geometry.
- Enter the required dimensions in your preferred unit (inches, feet, metres, centimetres, yards). For rectangles, enter length and width. For circles, enter the radius. For triangles, enter the base and height. The calculator supports decimal values for precise measurements.
- View the calculated area instantly with automatic unit conversions. Results are displayed in square inches, square feet, square metres, square centimetres, and square yards simultaneously, so you can use whichever unit your project requires.
- For complex areas, calculate multiple shapes and add the results together. An L-shaped room is two rectangles. A room with a bay window is a rectangle plus a triangle or trapezoid. Break any irregular floor plan into simple shapes for accurate calculations.
- Use the perimeter calculation (included for most shapes) alongside the area for fencing, baseboard, trim, and border material estimates. Perimeter tells you the total distance around the shape.
- Apply the results to real-world projects: multiply area by price per square foot for flooring costs, divide area by coverage rate for paint quantities, or use area with depth measurements to calculate material volumes for concrete, mulch, or gravel.
Frequently asked questions
How do I calculate the area of a rectangle?
Area = length x width. A room that is 14 feet long and 11 feet wide has an area of 154 square feet. Always use the same unit for both measurements. If one dimension is in feet and the other in inches, convert to the same unit first: 14 feet x 132 inches becomes 14 x 11 = 154 sq ft, or 168 x 132 = 22,176 sq inches. This calculator handles mixed units and conversions automatically.
How do I calculate the area of a triangle?
Area = (base x height) / 2. The height must be perpendicular (at a right angle) to the base, not the length of a side. For a triangle with a 10-foot base and 8-foot height: (10 x 8) / 2 = 40 square feet. If you know all three sides but not the height, use Heron's formula: Area = sqrt[s(s-a)(s-b)(s-c)] where s = (a+b+c)/2. This calculator supports both methods for triangles.
How do I calculate the area of a circle?
Area = pi x radius squared. A circle with a 5-foot radius has an area of 3.14159 x 25 = 78.54 square feet. If you know the diameter instead, divide it by 2 to get the radius. A 12-foot diameter circular patio has a radius of 6 feet and an area of 113.1 square feet. For semicircles (half circles), calculate the full circle area and divide by 2. Circular areas are common in landscaping, pool covers, and round table sizing.
What is the difference between area and perimeter?
Area measures the space inside a shape (square feet, square metres) and is used for flooring, paint, tile, and lawn coverage. Perimeter measures the total distance around the outside edge of a shape (linear feet, metres) and is used for fencing, baseboard, trim, and borders. A 10x12 foot room has an area of 120 square feet and a perimeter of 44 linear feet. You need 120 sq ft of flooring but 44 linear feet of baseboard for the same room.
How do I calculate area in square metres?
Enter dimensions in metres and the result is automatically in square metres. To convert from square feet to square metres, divide by 10.764. A 1,500 sq ft apartment is approximately 139 square metres. To convert square metres to square feet, multiply by 10.764. A 50 square metre condo is about 538 square feet. Square metres are the standard unit for area in most countries and are increasingly used in Canadian real estate, especially for condominium listings.
How do I calculate the area of an irregular shape?
Divide the irregular shape into a combination of rectangles, triangles, and circles. Calculate each sub-shape separately, then add the areas together. For L-shaped rooms, use two rectangles. For rooms with bay windows, add a triangle or trapezoid to the main rectangle. For curved sections, approximate with semicircles or quarter circles. For very complex shapes, use the grid method: overlay a grid of known squares, count the full squares, estimate partial squares, and multiply by the area of one grid square. For home improvement projects involving irregular floor plans, the
Square Footage Calculator is built specifically for room-by-room measurement and combines areas across multiple spaces automatically.
What is the area of common shapes?
Quick reference for standard shapes: rectangle = length x width, square = side x side, triangle = base x height / 2, circle = pi x radius squared, trapezoid = (top + bottom) / 2 x height, parallelogram = base x height, ellipse = pi x semi-major axis x semi-minor axis. For a hexagon: (3 x sqrt(3) / 2) x side squared. For an octagon: 2 x (1 + sqrt(2)) x side squared. This calculator supports all common shapes without requiring you to remember the formulas.
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