A rhombus looks like a tilted square: four equal sides, opposite angles equal, diagonals that cross at 90° and cut each other in half.
About this calculator
A rhombus looks like a tilted square: four equal sides, opposite angles equal, diagonals that cross at 90° and cut each other in half. When you know both diagonals, area is simply d₁×d₂/2 — the same rule as for any kite whose diagonals are perpendicular.
Each side length comes from half-diagonals as legs of a right triangle. Perimeter is 4s. A square is a special rhombus where diagonals are equal.
Rhombus math shows up in diamond floor tiles, crystal lattice sketches, and vector rhombus spanned by two edges. Compare with [[parallelogram]] when sides are not all equal, [[rectangle]] when angles are 90° and opposite sides match in pairs, and [[area]] for mixed 2D shapes.
Common uses
- Diamond tile area from measured diagonals on a floor plan
- Geometry homework — find side length from diagonals 10 and 8
- Verify that four equal fencing panels form a rhombus
- Crystal or lattice cell area estimates
- Kite-style land plots with perpendicular diagonals
Frequently asked questions
What is the area when diagonals are 10 and 8?
Area = 10 × 8 / 2 = 40 square units. Each side = √(5² + 4²) = √41 ≈ 6.40, so perimeter ≈ 25.61 units.
Is a square a rhombus?
Yes. A square has four equal sides and perpendicular diagonals of equal length. Every square satisfies the rhombus rules.
Why multiply diagonals and divide by 2?
The diagonals split the rhombus into four congruent right triangles. Together they fill half the bounding rectangle d₁×d₂.
Do I need side angles?
Not for area when both diagonals are known. Side length follows from half-diagonals alone because they meet at 90°.