- Volume Calculator
- Area Calculator
- Perimeter Calculator
- Surface Area Calculator
- Circle Calculator
- Rectangle Calculator
- Triangle Calculator
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Circle Inscribed in a Square CalculatorFind the radius, diameter, area and circumference of the largest circle inscribed in a square. Enter the side length and get instant results.
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Radius from Chord and Height CalculatorFind the radius of a circle or arc from its chord length and sagitta (height) using r = c²/(8h) + h/2. Free, instant, with diameter output.
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Sphere Circumference CalculatorCalculate the great-circle circumference of a sphere from its radius or diameter using C = 2πr. Fast, accurate, and free to use.
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Tangent Line Length from External Point CalculatorFind the length of a tangent line drawn from an external point to a circle. Enter the distance to the center and the radius to get L = √(d² − r²).
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Annulus Area & Circumference CalculatorCalculate the area, circumference, width and diameters of an annulus (flat ring) from any two dimensions: outer/inner radius, width, or diameters.
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Circle CalculatorFree circle calculator: enter radius, diameter, circumference or area and instantly get the other three, plus results expressed in terms of pi.
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Annulus CalculatorAnnulus calculator: enter any two of the outer/inner radius, circumference or area and solve all ring properties — radii, circumferences, areas and annulus area.
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Circular Segment CalculatorCalculate the area, chord, arc length, height (sagitta), apothem and perimeter of a circular segment from a circle's radius and central angle.
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Pie Chart Angle CalculatorConvert a value and total into a pie chart slice angle in degrees. Calculate the exact wedge angle and percentage for any category instantly.
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Aperture Area CalculatorCalculate the area of a circular aperture from its diameter using A = π(D/2)². Get instant results in mm² and cm² for lenses, pipes, and openings.
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Circumscribed Circle of a Rectangle CalculatorFind the circumscribed circle of a rectangle: enter side a and b to get the circumcircle radius, diameter, area, rectangle area and area ratio.
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Radius of a Circle CalculatorFind the radius of a circle from its diameter, circumference, or area. Free online calculator using r = C/(2π) = √(A/π) with instant results.
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Standard Equation of a Circle CalculatorFind the standard equation of a circle (x−h)²+(y−k)²=r² from center and radius. Also get diameter, circumference, area, and general form.
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Standard Form to General Form of a Circle CalculatorConvert a circle from standard form (x-h)²+(y-k)²=r² to general form x²+y²+Dx+Ey+F=0. Enter center and radius to get D, E, and F instantly.
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Square Inches of a Circle CalculatorCalculate the area of a circle in square inches from its radius or diameter using A = πr². Fast, accurate, and free circle area calculator.
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Square Footage of a Circle CalculatorFind the square footage (area in ft²) of a circle from its diameter or radius. Also shows circumference, square yards, and square meters.
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Quarter Circle CalculatorCalculate the area, arc length, and perimeter of a quarter circle from its radius. Free, instant quarter circle geometry calculator with worked example.
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Quarter Circle Area CalculatorCalculate the area of a quarter circle from its radius using A = πr²/4. Also returns the quarter arc length and full perimeter instantly.
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Quarter Circle Perimeter CalculatorCalculate the perimeter of a quarter circle from its radius using P = (πr/2) + 2r. Instant arc length and straight-edge breakdown.
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Perimeter of a Sector CalculatorCalculate the perimeter of a circular sector from its radius and central angle (degrees or radians). Uses P = 2r + rθ with the arc length.
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Inscribed Angle CalculatorCalculate the inscribed angle of a circle from its central angle. The inscribed angle equals half the central angle subtending the same arc.
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General to Standard Form of a Circle CalculatorConvert a circle equation from general form x²+y²+Dx+Ey+F=0 to standard form (x−h)²+(y−k)²=r². Find center and radius instantly.
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General Form of the Equation of a Circle CalculatorConvert a circle's center (h, k) and radius r into general form x² + y² + Dx + Ey + F = 0. Instantly find the D, E and F coefficients.
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Foci of an Ellipse CalculatorFind the foci of an ellipse from its semi-axes and center. Computes focal distance c, both focus coordinates, and eccentricity instantly.
