Pick a shape, enter its measurements and get the area in your unit, plus square metres, square feet, square yards, cents, acres and hectares. Useful for plots, rooms, flooring, paint and school geometry, with the formula worked out with your numbers.
Choose the shape.
Choose the unit you measured in.
Enter the measurements shown on the diagram.
Read the area and its conversions.
Rectangle: A = l × w
Triangle (Heron): A = √(s(s − a)(s − b)(s − c))
Triangle: A = ½ × b × h
Trapezium: A = (b₁ + b₂) ÷ 2 × h
Circle: A = π × r²
Sector: A = θ ÷ 360 × π × r²
Ellipse: A = π × a × b
Parallelogram: A = b × h
Rhombus: A = d₁ × d₂ ÷ 2
Area is the amount of flat surface inside a boundary, measured in square units. The area calculator covers ten shapes: rectangle, square, triangle from three sides or from base and height, trapezium, parallelogram, rhombus, circle, sector and ellipse. You choose the shape, the unit you measured in and the sizes marked on the drawing.
Along with the area in your unit, it converts the result to square metres, square feet, square yards, cents, acres and hectares. These are the units used when buying a plot, ordering tiles or flooring, estimating paint for a wall or checking a land record, so one measurement can be read in whichever form the seller, builder or document uses. Where it applies, the perimeter, circumference or arc length is shown too, which is what fencing and edging need.
1. Sketch the shape and decide which standard shape it matches, or split it into several.
2. Measure the sides in one unit. Heights must be perpendicular, not along a slanting side.
3. Use the formula for that shape, such as length × width for a rectangle.
4. For a triangle with three known sides, use Heron's formula with half the perimeter.
5. Add the areas of the pieces if you split the shape.
6. Convert to the unit you need, for example divide square feet by 9 for square yards.
A rectangle's area is length times width because that many unit squares fit inside it. Other formulas are found by rearranging shapes into rectangles. Cut a triangle off one end of a parallelogram and move it to the other end and you get a rectangle with the same base and height. A triangle is half of a parallelogram, which gives half base times height. A trapezium is the average of its two parallel sides times the height.
A circle cut into many thin slices and rearranged makes a shape close to a rectangle whose width is half the circumference, π r, and whose height is r. That gives the area π r². A sector is a fraction of the circle, the angle divided by 360, so its area is that fraction of π r². An ellipse is a circle stretched in one direction, and its area is π times its two semi-axes, a and b.
Plots are usually measured in feet and quoted in square feet or square yards, where one square yard, also called gajam, is nine square feet. Farm land is quoted in cents and acres: one acre is 43,560 square feet or 100 cents, and one hectare is about 2.47 acres. Units such as gunta, bigha, ground and kanal change from state to state, so always confirm the local size before using them in an agreement.
Ravi is buying a rectangular house plot that measures 40 feet by 60 feet and wants its size in square yards and cents.
Rectangle: formula: A = length × width
Put in your measurements: A = 60 × 40 = 2,400 ft²
Perimeter: 2 × (60 + 40) = 200 ft
In square metres: 1 ft² = 0.09290304 m² 2,400 ft² = 222.9673 m²
Answer: Area 2,400 ft²; Perimeter 200 ft; Square metres 222.9673 m²
Using a slanting side as the height of a triangle, trapezium or parallelogram.
Converting square feet to square yards by dividing by 3 instead of 9.
Mixing feet and inches or metres and feet in one calculation.
Entering three sides that cannot form a triangle, where one side is longer than the other two together.
Using the diameter for the radius of a circle, which makes the area four times too big.
Finding the size of a house plot or farm land in square yards, cents or acres.
Ordering tiles, flooring, carpet or false ceiling for a room.
Estimating paint for walls and ceilings.
Planning gardens, lawns and paved areas, including round and curved beds.
School geometry and mensuration problems.
How do I find the area of a plot in square yards?
Measure the plot in feet, choose its shape and read the square yards figure. 1 square yard is 9 square feet.
How many square feet are in a cent and an acre?
1 cent is 435.6 square feet and 1 acre is 43,560 square feet, which is 100 cents.
How do I find the area of a triangle from its three sides?
Use Heron's formula: find half the perimeter s, then take the square root of s(s − a)(s − b)(s − c). Choose Triangle (3 sides).
How do I measure an irregular plot?
Divide it into rectangles and triangles, find each area and add them together.
Is height the same as the slanting side?
No. Height is the perpendicular distance between the base and the opposite side or corner.