Rhombus Area CalculatorFree online math calculator — instant results, no sign-up
Calculate a rhombus's area from its diagonals.
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About the Rhombus Area Calculator
The Rhombus Area Calculator finds the area of a rhombus using the lengths of its two diagonals. It multiplies the diagonals and divides by two, so you do not need the side length or height. With the default diagonal lengths of 8 and 6, the area is 24 square units.
- First diagonal
- The length from one vertex to the opposite vertex, defaulting to 8 and measured in the same length unit as the second diagonal.
- Second diagonal
- The length between the other pair of opposite vertices, defaulting to 6 and measured in the same length unit as the first diagonal.
Formula and method
A = (d₁ × d₂) / 2; with the default inputs, A = (8 × 6) / 2 = 24.
- AArea of the rhombus, expressed in square units.
- d₁Length of the first full diagonal.
- d₂Length of the second full diagonal.
A rhombus's diagonals bisect each other at right angles, dividing it into four right triangles. Their combined area is half the product of the full diagonal lengths. For the default inputs, multiply 8 by 6 to get 48, then divide by 2 to get 24 square units.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- First diagonal8
- Second diagonal6
Results
- Result24
How to use the Rhombus Area Calculator
- 1Identify the two diagonals: each connects a pair of opposite vertices, rather than adjacent vertices.
- 2Measure both full diagonals and convert them to the same length unit if necessary.
- 3Enter 8 in First diagonal and 6 in Second diagonal to reproduce the default example, or enter your own measurements.
- 4Calculate the area using A = (d₁ × d₂) / 2.
- 5Read the result as square units; the default inputs give 24.
Reading your result
The Result row gives the area enclosed by the rhombus. With First diagonal = 8 and Second diagonal = 6, Result = 24 means 24 square units. If both diagonals are measured in centimeters, the area is in square centimeters; if they are measured in meters, it is in square meters.
Limitations
This tool assumes a flat rhombus and requires both full diagonal lengths in the same unit. For a nondegenerate rhombus, both lengths must be positive; a zero length produces zero area but does not describe a proper rhombus. Negative lengths are not geometrically valid. The formula is not valid for arbitrary quadrilaterals with nonperpendicular diagonals, and the result's accuracy depends on the accuracy of the measurements.
Common questions
Does it matter which diagonal I enter first?+
No. Multiplication is commutative, so entering 8 and 6 or 6 and 8 gives the same area of 24 square units.
Should I enter a full diagonal or the distance from the center to a vertex?+
Enter the full distance between opposite vertices. If you measured only from the center to a vertex, double that measurement before entering it because a rhombus's diagonals bisect each other.
Why is the product of the diagonals divided by two?+
The perpendicular diagonals form four right triangles, each with legs d₁/2 and d₂/2. Adding their areas gives 4 × (1/2) × (d₁/2) × (d₂/2) = d₁d₂/2.
Can I use this calculator for a square?+
Yes. A square is a rhombus with equal diagonals, so the same formula applies. Enter the square's full diagonal length in both fields.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.