Find the area and perimeter of a rectangle.
Area is length times width; perimeter is twice the sum of both sides.
Area: Length × width
Perimeter: 2 × (length + width)
A rectangle calculator takes length and width and gives you two numbers: the area, which is the space inside, and the perimeter, which is the distance around the edge. Area is length × width and perimeter is 2 × (length + width).
Rectangles are everywhere in Indian homes and property: rooms, tiles, plots, doors, notice boards and screens. Buying floor tiles or carpet depends on the area, while skirting, fencing, borders and wall trim depend on the perimeter. Real estate listings quote areas in square feet, and plots are often described as 30 × 40 or 40 × 60 feet, which this calculator turns into 1,200 or 2,400 square feet at once. Students meet both formulas from Class 4 or 5 onwards.
1. Measure the length and the width, the two sides that meet at a corner.
2. Convert both to the same unit, such as feet or metres.
3. Multiply them to get the area: A = length × width.
4. Add them and double the sum to get the perimeter: P = 2 × (length + width).
5. Write area in square units and perimeter in plain length units.
6. For an L-shaped room, split it into two rectangles, find each area and add them.
If a rectangle is 6 units long and 4 units wide, you can tile it with 6 unit squares in each row and 4 rows, giving 24 squares. That is what length × width counts. The idea extends to fractional sides: a 2.5 m by 1.5 m rectangle holds 3.75 square metres. Because area is built from length times length, converting units needs care: 1 m = 100 cm, but 1 m² = 10,000 cm², and 1 square yard is 9 square feet.
Area and perimeter are independent. A 12 × 3 rectangle and a 6 × 6 square both have area 36, but perimeters of 30 and 24. For a fixed perimeter, the square encloses the largest area; for a fixed area, the square needs the least boundary. This is why a square plot needs the least fencing for a given area, and why long, narrow shapes waste boundary. It is also a classic optimisation result from calculus.
Many area formulas are rectangles in disguise. A parallelogram is rearranged into a rectangle of the same base and height; a triangle is half of that. A cuboid's volume is a rectangle's area times the height, and its surface area is made of six rectangles. Even integration in calculus finds curved areas by adding up many thin rectangles. Understanding length × width well makes all of these easier.
Anil is retiling a bedroom that measures 14 feet by 11.5 feet and also needs skirting tiles along all four walls.
Answer: Area 161; Perimeter 51
Mixing units, such as length in feet and width in inches, without converting first.
Confusing area and perimeter when buying materials. Tiles need area; skirting needs perimeter.
Forgetting to double in the perimeter formula and using length + width only.
Converting square units with the linear factor, such as treating 1 m² as 100 cm².
Not subtracting door openings or adding 5 to 10% wastage when ordering tiles or skirting.
Estimating tiles, carpet, false ceiling or paint for rectangular rooms.
Finding plot areas in square feet or square metres for property deals.
Working out fencing, border or skirting length from the perimeter.
Sizing notice boards, banners and printed sheets.
Solving Class 5 to 8 mensuration problems and aptitude questions.
Does a square use the same formula?
Yes. A square is just a rectangle where the length and width are equal, so the same formulas work.