Area Calculator

Calculate the area and perimeter of various 2D shapes with precision. Get step-by-step calculations, unit conversions, and related measurements.

Rectangle

A quadrilateral with opposite sides equal and all angles 90°

Formula: A = length × width
Examples: Doors, Windows, TV screens, Book pages, Playing fields

Longer dimension

Shorter dimension

Examples

• Calculate the area of a room (rectangle)
• Find the area of a circular garden
• Determine the area of a triangular plot of land
• Calculate the area of a hexagonal tile

How to Use the Area Calculator

Our comprehensive area calculator supports multiple 2D shapes and provides detailed calculations with explanations:

  1. Select the 2D shape you want to calculate from the dropdown menu
  2. Choose your preferred unit of measurement (mm, cm, m, in, ft, etc.)
  3. Enter the required dimensions for your selected shape
  4. For triangles, choose between base-height or three-sides method
  5. Click "Calculate Area" to get comprehensive results

The calculator provides step-by-step calculations, perimeter measurements, and automatic conversions to multiple units for complete analysis.

Supported 2D Shapes

Basic Quadrilaterals

  • Square: A = side² - All sides equal, all angles 90°
  • Rectangle: A = length × width - Opposite sides equal, all angles 90°
  • Parallelogram: A = base × height - Opposite sides parallel
  • Trapezoid: A = ½(base₁ + base₂) × height - One pair of parallel sides

Triangles

  • Base-Height Method: A = ½ × base × height - Standard formula
  • Heron's Formula: A = √(s(s-a)(s-b)(s-c)) - When all three sides are known
  • Triangle Inequality: Automatically validated for three-side calculations

Curved Shapes

  • Circle: A = πr² - Perfect round shape
  • Ellipse: A = π × a × b - Oval shape with two axes
  • Circular Sector: A = (θ/360°) × πr² - Slice of a circle
  • Annulus (Ring): A = π(R² - r²) - Area between two circles

Regular Polygons

  • Pentagon: A = ¼√(25 + 10√5) × side² - Five equal sides
  • Hexagon: A = (3√3/2) × side² - Six equal sides
  • Octagon: A = 2(1 + √2) × side² - Eight equal sides

Understanding Area and Perimeter

Area and perimeter are fundamental measurements in geometry with practical applications in construction, design, and everyday planning.

Area Concepts

  • Definition: Amount of 2D space enclosed by a shape
  • Units: Square units (cm², m², ft², etc.)
  • Applications: Floor space, material coverage, land measurement
  • Scaling: Area increases with the square of linear dimensions

Perimeter Concepts

  • Definition: Total distance around the boundary of a shape
  • Units: Linear units (cm, m, ft, etc.)
  • Applications: Fencing, borders, trim materials
  • Special Cases: Circumference for circles, arc length for sectors

Mathematical Properties

  • Isoperimetric Problem: Circles have maximum area for given perimeter
  • Regular Polygons: As sides increase, they approach circular properties
  • Composite Shapes: Total area equals sum of component areas
  • Coordinate Geometry: Can be calculated using coordinate formulas

Real-World Applications

Construction and Architecture

  • Floor Planning: Room areas for space allocation and HVAC sizing
  • Material Estimation: Flooring, roofing, and wall coverage calculations
  • Land Development: Plot area measurements and zoning compliance
  • Structural Design: Cross-sectional areas for load calculations

Landscaping and Agriculture

  • Garden Design: Planting area calculations and material needs
  • Irrigation Planning: Coverage area for sprinkler systems
  • Crop Planning: Field area calculations for yield estimation
  • Fencing Projects: Perimeter calculations for boundary planning

Manufacturing and Design

  • Material Optimization: Minimizing waste in cutting operations
  • Product Design: Component sizing and assembly planning
  • Quality Control: Dimensional verification and tolerance checking
  • Cost Estimation: Material costs based on area calculations

Advanced Calculation Methods

Triangle Area Methods

Our calculator supports multiple methods for triangle area calculation:

  • Base-Height Formula: A = ½ × base × height - Most common method
  • Heron's Formula: A = √(s(s-a)(s-b)(s-c)) - When all sides are known
  • Coordinate Method: Using vertex coordinates (advanced)
  • Trigonometric: A = ½ab sin(C) - Using two sides and included angle

Regular Polygon Properties

Regular polygons have special relationships between their dimensions:

  • Apothem: Distance from center to side midpoint
  • Circumradius: Distance from center to vertex
  • Central Angle: 360°/n where n is number of sides
  • Interior Angle: (n-2) × 180°/n

Curved Shape Calculations

  • Circular Sectors: Partial areas based on central angle
  • Ellipse Approximations: Ramanujan's perimeter formula
  • Annulus (Ring): Difference between two circular areas
  • Arc Length: s = rθ (in radians) for sector calculations

Unit Conversions and Measurements

Understanding unit conversions is essential for area calculations across different measurement systems and practical applications.

Common Area Units

Metric Units

  • 1 m² = 10,000 cm² = 1,000,000 mm²
  • 1 hectare = 10,000 m²
  • 1 km² = 100 hectares = 1,000,000 m²

Imperial Units

  • 1 ft² = 144 in²
  • 1 yd² = 9 ft² = 1,296 in²
  • 1 acre = 43,560 ft² = 4,840 yd²
  • 1 mi² = 640 acres

Land Measurement Units

  • Acre: Traditional agricultural unit (43,560 ft²)
  • Hectare: Metric land unit (10,000 m²)
  • Square Mile: Large area measurement (640 acres)
  • Square Kilometer: Metric equivalent (100 hectares)

Conversion Tips

  • Always square the linear conversion factor for area
  • Use consistent units throughout calculations
  • Double-check conversions for accuracy
  • Consider precision requirements for your application
  • Use appropriate significant figures based on measurement accuracy

Formula Reference Guide

Quick reference for area formulas of common shapes with their mathematical derivations and practical considerations.

Basic Shape Formulas

Quadrilaterals

  • Square: A = s²
  • Rectangle: A = l × w
  • Parallelogram: A = b × h
  • Trapezoid: A = ½(b₁ + b₂) × h

Curved Shapes

  • Circle: A = πr²
  • Ellipse: A = πab
  • Sector: A = (θ/360°) × πr²
  • Annulus: A = π(R² - r²)

Advanced Formulas

  • Triangle (Heron's): A = √(s(s-a)(s-b)(s-c)) where s = (a+b+c)/2
  • Regular Pentagon: A = ¼√(25 + 10√5) × s²
  • Regular Hexagon: A = (3√3/2) × s²
  • Regular n-gon: A = ¼ns² × cot(π/n)

Mathematical Constants

  • π (Pi): ≈ 3.14159 - Essential for circular calculations
  • √2: ≈ 1.414 - Diagonal ratio for squares
  • √3: ≈ 1.732 - Important for hexagonal calculations
  • Golden Ratio: φ ≈ 1.618 - Appears in pentagon formulas