Cylindrical to Cartesian Converter

Cartesian x, y and z for a cylindrical point, rounded to two decimals.

How it is calculated

The converter reads three numbers: the radius r (distance from the z-axis), the angle θ in degrees, and the height z. It first turns the angle into radians, t = θ × π / 180, then computes x = r·cos(t) and y = r·sin(t). The height is passed through unchanged, and if you leave z empty it is treated as 0. All three results are rounded to two decimals, so a value that should be exactly zero (such as x at 90°) shows as 0.00. A negative radius is accepted and simply points the opposite way (the same as adding 180° to the angle), and angles beyond 360° wrap around naturally.

Worked example

Take r = 5, θ = 30° and z = 2. Convert the angle: 30 × π / 180 ≈ 0.5236 rad. Then x = 5 × cos(30°) = 5 × 0.8660 = 4.33, and y = 5 × sin(30°) = 5 × 0.5 = 2.50. The height carries over, so z = 2.00. The Cartesian point is (4.33, 2.50, 2.00).

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Common mistakes

  • Entering the angle in radians. The field expects degrees, so 1.57 is treated as a bit under 2 degrees, not a quarter turn.
  • Mixing up the roles of r and z: r is the distance from the axis in the xy-plane, not the straight-line distance from the origin (that is the spherical radius).
  • Measuring θ from the y-axis. Here it is measured counter-clockwise from the positive x-axis.
  • Expecting z to change. Cylindrical and Cartesian share the same z, so it is only reformatted.
  • Reading a rounded 0.00 as an exact zero when the inputs were not clean angles; the displayed values are rounded to two decimals.

About this calculator

Cylindrical coordinates locate a point by radius r (distance from the z-axis), angle θ (measured from the x-axis in the xy-plane), and height z. Converting to Cartesian (x, y, z) uses x = r·cos(θ), y = r·sin(θ), and z stays unchanged, giving a point's position in the standard rectangular system.

This conversion is routine in mechanical and electrical engineering, robotics, and 3D graphics, wherever a system is naturally described with a radius and rotation angle — such as a machined part on a lathe, a robotic arm's swing, or a magnetic field around a wire — but needs to be combined with Cartesian data from CAD models or physics simulations.

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