How do I find a rhombus's area?
Multiply the two diagonals and halve the result: half of d1 times d2. The diagonals are the lines joining opposite corners.
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Rhombus Area Calculator
Find a rhombus's area from its two diagonals, and its perimeter from the side length (which the diagonals also give you).
area = ½×d₁×d₂ ; side = ½√(d₁²+d₂²) ; perimeter = 4×side
Frequently asked questions
Why does the diagonal method work?
Because a rhombus's diagonals cross at right angles and cut it into four right triangles. Half the product of the diagonals neatly totals their area.
How do I get the side and perimeter?
The diagonals bisect each other at right angles, so each half-diagonal forms a right triangle. The side is half the square root of d1 squared plus d2 squared, and the perimeter is four times that.
Is a rhombus a square?
A square is a special rhombus with right angles and equal diagonals. A general rhombus has equal sides but its angles are not 90 degrees.
Where is this useful?
Diamond-shaped tiles, kite design, jewellery, and patterns where you know the diagonals more easily than the angles.