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Rectangle Calculator
Enter width and height — area, perimeter and diagonal update instantly.
Formula
Area = w·h | Perimeter = 2(w+h) | Diagonal = √(w²+h²)
Example
2000 × 1000 mm plate → Area = 2 m², perimeter = 6 m, diagonal = 2236 mm.
FAQ
How do I find a rectangle diagonal?
Apply the Pythagorean theorem to width and height: d = √(w²+h²).
Is a square a rectangle?
Yes — a square is a rectangle with all four sides equal, so all rectangle formulas apply.