Geometry

  • Curved Surface Area of a Cylinder Calculator
    Calculate the curved (lateral) surface area of a cylinder instantly using CSA = 2πrh. Enter the radius and height to get the result in square units.
  • Volume of a Rectangular Prism Calculator
    Calculate the volume of a rectangular prism (box) instantly with V = l × w × h. Also computes total surface area. Free, fast, and accurate.
  • Area of a Trapezoid Calculator
    Calculate the area of a trapezoid instantly from its two parallel bases and height using A = ½(b₁ + b₂)·h. Free, fast, and accurate.
  • Circumference of a Circle Calculator
    Calculate the circumference of a circle from radius or diameter using C = 2πr = πd. Get circumference, diameter, and area instantly with worked examples.
  • Volume of a Cone Calculator
    Calculate the volume of a cone instantly from its radius and height using V = (1/3)πr²h. Free, accurate cone volume calculator with worked example.
  • Number of Diagonals of a Polygon Calculator
    Find how many diagonals a polygon has from its number of sides using D = n(n−3)/2. Fast, free, and works for any polygon with 3 or more sides.
  • Surface Area of a Cube Calculator
    Calculate the total surface area of a cube from its edge length using SA = 6s². Also shows the area of one face and the cube's volume.
  • 3D Distance Calculator
    Calculate the straight-line distance between two points in 3D space using their (x, y, z) coordinates with the 3D Euclidean distance formula.
  • Cosine of an Angle Calculator
    Calculate the cosine of an angle in a right triangle from the adjacent side and hypotenuse, plus the angle θ in degrees and radians.
  • Right Triangle Angles from Two Legs Calculator
    Find both acute angles of a right triangle from its two legs. Enter legs a and b to get angle A = atan(a/b), angle B = 90 - A, and the hypotenuse.
  • Rectangle Gravel/Mulch Volume Calculator
    Calculate how many cubic yards of gravel, mulch, sand or topsoil you need to fill a rectangular area at a given depth. Enter length, width and depth.
  • Shadow Length & Sun Angle Calculator
    Calculate shadow length from the sun's elevation angle, or find the sun angle from an object's height and shadow length using simple trigonometry.
  • Sine of an Angle Calculator
    Calculate the sine of an angle in a right triangle from the opposite side and hypotenuse, then find the angle θ in degrees and radians using arcsine.
  • Law of Cosines Angle Calculator
    Find the angle of a triangle from its three side lengths using the law of cosines. Enter sides a, b, and c to get angle C in degrees and radians.
  • Rectangular Concrete Slab Volume Calculator
    Calculate how many cubic yards of concrete you need for a rectangular slab from its length, width, and thickness. Fast, accurate, and free.
  • Paint Needed for a Rectangular Wall Calculator
    Calculate how many gallons of paint you need for a rectangular wall from its length, height, coverage per gallon, and number of coats.
  • Rectangular Lumber Board Feet Calculator
    Calculate board feet of rectangular lumber from length, width and thickness in inches. Multiply by board count for total BF instantly.
  • Rectangular Pool Volume Calculator
    Calculate how many gallons of water your rectangular pool holds. Enter length, width, and average depth in feet to get the volume instantly.
  • Square Yards of a Rectangle Calculator
    Convert a rectangle's length and width in feet to square yards instantly. Enter dimensions to get area in square yards and square feet.
  • Circle to Cylinder Volume Calculator
    Turn a circle's radius and a height into a cylinder volume instantly with V = πr²h. Free calculator showing circle area and total cubic volume.
  • Rectangle Area Moment of Inertia Calculator
    Calculate the area moment of inertia (Ix and Iy) of a rectangular cross-section about its centroidal axes from width and height.
  • Circumference to Area Calculator
    Convert a circle's circumference to its area instantly with A = C²/(4π). Also shows radius and diameter. Free, accurate geometry calculator.
  • Diameter from Radius Calculator
    Find a circle's diameter from its radius instantly using d = 2r. Also returns circumference and area. Fast, free, and accurate geometry tool.
  • Radius from Circumference Calculator
    Find a circle's radius from its circumference using r = C / (2π). Also returns diameter and area instantly. Free, accurate geometry calculator.

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