- Volume Calculator
- Area Calculator
- Perimeter Calculator
- Surface Area Calculator
- Circle Calculator
- Rectangle Calculator
- Triangle Calculator
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Circumference from Radius CalculatorCalculate the circumference of a circle from its radius using C = 2πr. Instantly get circumference, diameter, and area from any radius value.
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Radius from Area of a Circle CalculatorFind the radius of a circle from its area using r = √(A/π). Instantly get radius, diameter, and circumference for any circle area.
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Sector Area Calculator (Degrees)Calculate the area of a circle sector from the radius and central angle in degrees. Free, instant, with arc length too. Formula A = (θ/360)·π·r².
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Diameter from Area CalculatorFind a circle's diameter from its area using d = 2√(A/π). Instantly get diameter, radius, and circumference from any area value.
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Area from Circumference CalculatorFind the area of a circle from its circumference using A = C² / (4π). Also returns radius and diameter instantly. Free online geometry calculator.
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Partially Filled Circle Area CalculatorCalculate the filled cross-section area and fill percentage of a partially filled circle or cylindrical tank from radius and fill depth.
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Circle Moment of Inertia (Area) CalculatorCalculate the area moment of inertia of a solid circle from its radius or diameter using I = πr⁴/4 = πd⁴/64. Free engineering tool.
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Circle Circumference from Area CalculatorFind the circumference of a circle from its area instantly. Enter the area and get the circumference, radius, and diameter using C = 2√(πA).
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Radius from Circumference CalculatorFind the radius of a circle from its circumference using r = C / (2π). Also returns diameter and area instantly in the same unit.
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Diameter from Circumference CalculatorFind the diameter of a circle from its circumference using d = C / π. Instantly calculate diameter and radius from any circumference value.
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Circle Area from Circumference CalculatorFind a circle's area directly from its circumference using A = C² / (4π). Instant, accurate results plus the radius and diameter.
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Circle Area and Circumference CalculatorCalculate a circle's area, circumference, radius, and diameter from any one known value using A = πr² and C = 2πr. Fast and accurate.
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Diameter from Circumference CalculatorFind a circle's diameter from its circumference using d = C / π. Instantly get diameter, radius, and area for any circumference value.
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Radius from Diameter CalculatorFind the radius of a circle from its diameter instantly. Enter any diameter and this calculator returns the radius using r = d/2.
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Radius from Area CalculatorCalculate the radius of a circle from its area using r = √(A/π). Also returns diameter and circumference instantly. Free online geometry tool.
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Arc Length CalculatorCalculate the arc length of a circle from its radius and central angle in degrees or radians. Also shows chord length and circumference.
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Circle Area CalculatorCalculate the area of a circle instantly with A = πr². Enter the radius to get area, diameter, and circumference in seconds.
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Semicircle Perimeter CalculatorCalculate the perimeter of a semicircle from its radius using P = πr + 2r = r(π + 2). Free, instant, and shows the arc and diameter parts.
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Circle Perimeter from Diameter CalculatorCalculate the perimeter (circumference) of a circle from its diameter using C = πd. Instantly get circumference, radius, and area for any diameter.
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Circle Area from Diameter CalculatorFind the area of a circle from its diameter instantly. Uses A = πd²/4. Also shows radius and circumference. Fast, free, and accurate.
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Area of a Circle CalculatorCalculate the area of a circle from its radius using A = πr². Also returns the diameter and circumference instantly. Free online geometry tool.
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Circle Through Three Points CalculatorFind the equation of a circle passing through three points. Get center (h,k), radius, area, and circumference instantly with full step-by-step formula.
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Sagitta CalculatorCalculate the sagitta (arc height) of a circular segment from radius and chord length, plus arc length and central angle. Free online geometry tool.
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Sector Area from Arc Length CalculatorCalculate the area of a circular sector from its radius and arc length using A = ½ · r · s. Fast, accurate, and free online sector area tool.
