Area Calculators
This category presents calculators for determining the area of two-dimensional shapes. Each tool provides numerical outputs for circles, polygons, curved sections and other flat forms defined by standard geometric relationships.
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Annulus Area Calculator
A ring-shaped region has an area determined by the difference between its outer and inner circular boundaries.
Example use: Estimating the surface area of a circular track around a field.
Inputs: outer radius, inner radius
Outputs: area, ring thickness, average circumference, aspect ratio
Visual: shows the outer circle, inner circle, and the shaded ring between them
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Circle Area Calculator
A circle's size is fully determined by its radius, which sets its width, boundary length, and enclosed area.
Example use: Working out the area covered by a round tabletop.
Inputs: radius length
Outputs: diameter, circumference, area
Visual: shows a circle with its radius marked
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Circle Segment Area Calculator
A circular segment is formed when a straight line cuts across a circle, creating a curved region with a specific shape and boundary.
Example use: Estimating the area of a slice formed by cutting across a circular pond.
Inputs: radius, central angle
Outputs: area, arc length, chord length, segment perimeter, segment height, apothem, triangle area, sector area
Visual: shows the curved segment, its chord, radii, and apothem
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Ellipse Area Calculator
An ellipse is defined by two perpendicular half-lengths that determine its area, shape, and focal spacing.
Example use: Estimating the area of an oval running track.
Inputs: semi-major axis, semi-minor axis
Outputs: area, approximate circumference, eccentricity, focal distance
Visual: shows the ellipse outline and the two focal points
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Kite Area Calculator
A kite shape is set by two diagonals that meet at right angles, giving it a distinct area and angle structure.
Example use: Working out the area of a decorative kite-shaped tile.
Inputs: diagonal 1, diagonal 2, intersection ratio on diagonal 1
Outputs: area, perimeter, side lengths, top angle, bottom angle, side angles
Visual: shows the kite with both diagonals drawn
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Parallelogram Area Calculator
A parallelogram's area depends on its base and the perpendicular height between its opposite sides.
Example use: Estimating the area of a slanted garden bed outline.
Inputs: base length, perpendicular height
Outputs: area, equivalent rectangle, aspect ratio, square‑equivalent side length, triangle‑equivalent height, area per unit base/height, area efficiency
Visual: shows the slanted sides and the perpendicular height
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Rectangle Area Calculator
A rectangle is defined by its length and width, which determine its area, boundary length, and diagonal.
Example use: Working out the floor area of a room.
Inputs: length, width
Outputs: area, perimeter, diagonal length, aspect ratio, squareness index, diagonal angle, compactness ratio
Visual: shows the rectangle with its diagonal marked
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Regular Hexagon Area Calculator
A regular hexagon has equal sides and angles, giving it a fixed relationship between its side length, apothem, and area.
Example use: Estimating the area of a hexagonal paving stone.
Inputs: side length
Outputs: apothem, circumradius, perimeter, area, interior and exterior angles, flat‑to‑flat width, point‑to‑point width, central angle
Visual: shows the hexagon with its incircle
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Regular Pentagon Area Calculator
A regular pentagon's equal sides and angles define its area, apothem, and circumscribed circle.
Example use: Estimating the area of a five-sided tabletop.
Inputs: side length
Outputs: area, perimeter, apothem, circumradius, diagonal, height, interior, exterior and central angles
Visual: shows the pentagon with its apothem and circumradius
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Regular Polygon Area Calculator
A regular polygon with equal sides and angles has predictable angle sums, radii, and area based on its side count.
Example use: Estimating the area of a multi-sided decorative panel.
Inputs: number of sides, side length
Outputs: central angle, interior angle, exterior angle, sum of interior angles, apothem, circumradius, perimeter, area
Visual: shows the polygon with its circumscribed circle
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Rhombus Area Calculator
A rhombus has four equal sides, and its diagonals determine its area and the size of its inscribed circle.
Example use: Estimating the area of a rhombus-shaped window.
Inputs: diagonal 1, diagonal 2
Outputs: area, side length, height, perimeter, incircle radius, angles, diagonal ratio
Visual: shows the rhombus with its diagonals and inscribed circle
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Sector Area Calculator
A circular sector is defined by a radius and an angle, giving it a curved boundary and a specific enclosed area.
Example use: Estimating the area of a slice of a circular garden bed.
Inputs: radius, central angle
Outputs: sector area, circular fraction, inner triangle area, arc length, total perimeter
Visual: shows the sector with its arc and radii
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Square Area Calculator
A square's equal sides determine its area, boundary length, diagonal, and the sizes of its inscribed and circumscribed circles.
Example use: Working out the area of a square patio.
Inputs: side length
Outputs: area, perimeter, diagonal, inradius, circumradius, diagonal ratio, triangle area
Visual: shows the square with its diagonal
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Trapezium Area Calculator
A trapezium has one pair of parallel sides, and its area depends on those sides and the vertical height between them.
Example use: Estimating the area of a slanted plot outline.
Inputs: parallel side a, parallel side b, vertical height
Outputs: area, median, slant height (isosceles), perimeter (isosceles), diagonal length, triangle area
Visual: shows the trapezium with its median marked
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Trapezoid Area Calculator
A trapezoid's area is set by its two bases and the perpendicular height between them.
Example use: Working out the area of a tapered garden bed.
Inputs: base 1 length, base 2 length, perpendicular height
Outputs: area, perimeter, median
Visual: shows the trapezoid with its median
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Triangle Area Calculator
A triangle's area is determined by its base and the perpendicular height from that base to the opposite corner.
Example use: Estimating the area of a triangular patch of grass.
Inputs: base, height
Outputs: area, minimum possible perimeter, side of equivalent square
Visual: shows the triangle with its bounding box
Area Calculators FAQs
Area describes the size of a flat region enclosed by a shape's boundaries. It is expressed in square units and represents the total surface covered by the shape.
The required measurements depend on the shape and may include radius, side lengths, base, height, diagonals or angles. Each calculator identifies the values needed for its specific formula.
Different regions use different names for the same shape. In the UK, a shape with one pair of parallel sides is called a trapezium, while in the US it is called a trapezoid. Both terms refer to the same form, and the area formula is identical in each case.