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Rectangle Area Calculator

A rectangle is an equiangular quadrilateral with four right angles and opposite sides of equal length. This free Rectangle Area Calculator computes th

Mathematics
Formula & Methodology
Area = Length × Width = l × w Perimeter = 2 × (Length + Width) = 2(l + w) Diagonal = √(Length² + Width²)

To compute the area of a rectangle: 1. Measure the length (l) of the longer side. 2. Measure the width (w) of the shorter adjacent side. 3. Multiply length by width: Area = l × w. The perimeter is twice the sum of length and width: 2(l + w). The diagonal distance is determined via the Pythagorean theorem: d = √(l² + w²).

Rectangle Area

96

Overview

A rectangle is an equiangular quadrilateral with four right angles and opposite sides of equal length. This free Rectangle Area Calculator computes the exact square area, perimeter, and corner-to-corner diagonal distance for any rectangle.

Rectangle area is the most frequently calculated geometric metric in daily life—used for room flooring, drywall, television screens, yard landscaping, and solar panel arrays.

Worked Examples

Example 1: Room Measuring 12 ft × 8 ft

Inputs: Length = 12, Width = 8

  1. Area: 12 × 8 = 96 sq ft.
  2. Perimeter: 2 × (12 + 8) = 2 × 20 = 40 ft.
  3. Diagonal: √(12² + 8²) = √(144 + 64) = √208 ≈ 14.42 ft.
Final Answer: Area: 96.00 sq ft, Perimeter: 40.00 ft

Example 2: Sports Field (100m × 64m)

Inputs: Length = 100, Width = 64

  1. Area: 100 × 64 = 6,400 sq meters.
  2. Perimeter: 2 × 164 = 328 meters.
Final Answer: 6,400.00 sq m

Example 3: Solar Panel (1.8m × 1.1m)

Inputs: Length = 1.8, Width = 1.1

  1. Area: 1.8 × 1.1 = 1.98 sq meters.
Final Answer: 1.98 sq m

How to Use This Calculator

  1. Enter the rectangle length into the first field.
  2. Enter the rectangle width into the second field.
  3. Click "Calculate" to determine the area.
  4. Review the perimeter and diagonal values below.
  5. Click "Reset" to analyze another rectangle.

Reference Table

Length (l)Width (w)PerimeterArea (l × w)
531615.00
1042840.00
1284096.00
151050150.00
201570300.00

Frequently Asked Questions

Is a square a rectangle?
Yes. A square is a special case of a rectangle where all four sides are equal in length.
How do you calculate flooring waste from rectangle area?
Contractors typically add 10% to total room area to account for cuts, trimming, and waste: Total Flooring Needed = Area × 1.10.
How do you find the diagonal of a rectangle?
The diagonal divides the rectangle into two right triangles. Use the Pythagorean theorem: Diagonal = √(Length² + Width²).
Does it matter which side is labeled length and which is width?
No. Multiplication is commutative (l × w = w × l), so swapping length and width produces identical area and perimeter.
How do you convert square feet to square meters?
Divide square feet by 10.764 (or multiply by 0.0929). For example, 100 sq ft ≈ 9.29 sq m.

Related Calculators

🧮Square Area Calculator🧮Area Calculator🧮Perimeter Calculator🧮Pythagorean Theorem Calculator
Reviewed & Authored by: Dr. Elizabeth Vance, PhD Applied Mathematics · Last Updated: 2026-10-06
Computed via elementary Euclidean quadrilateral geometry.