Area Calculator

Calculate area and perimeter for rectangles, circles, triangles, trapezoids, and ellipses.
Shape

Area

50.00

Perimeter

30.00

Calculation

Formula10.00 × 5.00
Area50.0000
Perimeter30.0000

Use the Area Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

Our Area Calculator simplifies the computation of area and perimeter for common geometric shapes: rectangles, circles, triangles, trapezoids, and ellipses. This tool is invaluable for students, engineers, and DIY enthusiasts who need quick and accurate measurements for projects ranging from home renovations to complex design work, saving time and reducing error in 2026's fast-paced environment.

For rectangles, area is length * width and perimeter is 2 * (length + width). Circles use π * radius² for area and 2 * π * radius for perimeter. Triangles utilize 0.5 * base * height for area, with perimeter being the sum of all three sides. Trapezoids calculate area as 0.5 * (base1 + base2) * height, and ellipses use π * semi-major axis * semi-minor axis for area, with an approximate perimeter formula often involving an elliptic integral.

Ensure you use consistent units for all measurements (e.g., all meters or all feet) to avoid incorrect results. For triangles, always use the perpendicular height to the base, not a slanted side. When dealing with ellipses, be mindful that the perimeter calculation is an approximation unless using advanced methods, so understand the limitations of the formula provided.

Calculating the Area and Perimeter of a New Circular Park in Austin

  1. 1 A new circular park is being designed in Austin, scheduled for completion in late 2026. The architects have specified a radius of 150 meters for the main green space.
  2. 2 Using the Area Calculator, input 'Circle' as the shape and '150' as the radius. The calculator will then apply the formulas: Area = π * (150 m)² and Perimeter = 2 * π * (150 m).
  3. 3 The calculated area of the park is approximately 70,685.8 square meters, and the perimeter is approximately 942.5 meters.
  4. 4 This means the park will cover an area equivalent to about 17.5 acres, providing ample green space for recreation. A perimeter of 942.5 meters indicates a walking path around the park would be just under a kilometer, perfect for a leisurely stroll.

Source: Khan Academy · Last updated: April 2026

Frequently Asked Questions

How do you calculate the area of a circle?
Area of a circle equals pi times the radius squared. For a circle with a 5-foot radius, the area is 3.14159 times 25 = 78.54 square feet.
How do you convert square feet to acres?
Divide the square footage by 43,560. For example, 10,000 square feet equals about 0.23 acres. One acre is 43,560 square feet, roughly the size of a football field without the end zones.
How do you calculate the area of an irregular shape?
Break the irregular shape into simple shapes (rectangles, triangles, circles), calculate each area separately, and add them together. For odd-shaped rooms, divide into rectangular sections.

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