Calculate area, perimeter and diagonal of a rectangle from length and width.
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Right triangles, areas, slopes, distances and common coordinate-geometry formulas.
Enter the requested values above and select Calculate. The result updates immediately on the page, so you can change one value and compare different scenarios without leaving the calculator.
A 12 by 8 rectangle has area 96 and perimeter 40.
Calculate area, perimeter and diagonal of a rectangle from length and width. It is designed for quick estimates and everyday problem solving. When a calculation affects a contract, tax filing, medical decision or other high-stakes situation, verify the result with the appropriate professional or authoritative source.
A rectangle 12 by 8 units has area 96 square units, perimeter 40 units and diagonal about 14.42 units.
Area, perimeter and diagonal answer different measurement questions.
Keep length and width in matching units and use the same units for every side.
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Calculate area, perimeter and diagonal of a rectangle from length and width.
Area = length × width. Perimeter = 2(length + width). Diagonal = √(length² + width²).
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