Area of Rectangle Calculator

Calculate rectangle area instantly. Free online rectangle area calculator with length and width inputs.

The Area of Rectangle Calculator computes the area of any rectangle using its length and width. This fundamental geometry tool is essential for floor planning, construction, landscaping, and countless practical applications. Simply enter your dimensions to get the area instantly, with support for various units and clear formula explanation.

Common use cases

  • Room and floor area calculations
  • Garden and lawn sizing
  • Paint coverage estimation
  • Flooring material calculations
  • Construction planning

How to use

  1. Enter the length of the rectangle
  2. Enter the width of the rectangle
  3. Click calculate for the area
  4. View the formula: Area = length × width
  5. Copy results for your project

FAQ

What is the formula for rectangle area?

Area = length × width. For a 5m × 3m rectangle: Area = 15 m².

Does it matter which dimension is length vs width?

No, multiplication is commutative. 5 × 3 = 3 × 5 = 15.

How do I convert between area units?

Use our unit converters. Common: 1 m² = 10.764 ft², 1 acre = 43,560 ft².

What if my shape isn't a perfect rectangle?

Break irregular shapes into rectangles, calculate each, and sum the areas.