2D · quadrilateral
Rectangle
Four right angles and two pairs of equal opposite sides make the rectangle a useful model for rooms, screens, and sheets of paper.
RectangleChange a dimension to explore
A = w × hDimensions shown in the selected unit
Give your shape a size.
Use the same unit for every dimension. Changing the unit relabels the measurements; it does not convert them.
From dimensions to an answer
Know its properties
| Sides | 4; opposite pairs are equal |
| Interior angles | Four 90° angles |
| Diagonals | Equal in length; bisect each other |
| Symmetry | 2 reflection axes; 4 for a square |
Useful formulas
Area: A = wh
Perimeter: P = 2(w + h)
Diagonal: d = √(w² + h²)
A little question. A clearer picture.
Rectangle: common questions
Wondering about the why? Start here.
How do I calculate a rectangle’s area and perimeter?
Multiply width by height for area: A = wh. Add width and height and double the result for perimeter: P = 2(w + h). A 6 cm by 4 cm rectangle has area 24 cm² and perimeter 20 cm.
Compare area and perimeterIs a square also a rectangle?
Yes. A rectangle has four right angles, and a square satisfies that definition with all four sides equal. Enter the same width and height to calculate a square’s area and perimeter.
Explore regular polygons