Utilize our free online calculator to determine the length and width of a rectangle when its area is known. Simply input the total area and an optional aspect ratio (length-to-width) to instantly find the precise dimensions you need. Perfect for geometry, design, or construction tasks.
Formula:
The area of a rectangle (A) is found by multiplying its length (L) by its width (W):
A = L × W
If you also know the aspect ratio (R), which is Length divided by Width (R = L / W), then L = R × W.
Substituting L into the area formula:
A = (R × W) × W = R × W2
Solving for Width (W):
W = √(A / R)
And then solving for Length (L):
L = R × W = √(R × A)
Note: If no aspect ratio is provided, it defaults to 1 (a square), where L = W = √(A).
- A: Area of the rectangle
- R: Aspect Ratio (Length / Width)
- L: Length of the rectangle
- W: Width of the rectangle