Cycloid Calculator

Calculate cycloid point coordinates, single-arch length, arch area, and period from the rolling circle radius and parameter t.

807.8K uses Updated · 2026-05-06 Runs locally · zero upload
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How to Use Cycloid Calculator

The Cycloid Calculator computes the key properties of a standard cycloid from just two inputs. Enter the rolling circle radius and optionally a specific value of the parameter t to get point coordinates and arch properties.

  1. Enter the radius r — type the radius of the rolling circle in any consistent unit.
  2. Enter parameter t (optional) — type a value in radians (e.g., π ≈ 3.14159) to compute the coordinates of a specific point on the cycloid.
  3. Read the results — the Cycloid Calculator shows the x and y coordinates of the point at t, as well as the single-arch length, arch area, and period for the given radius.

The arch properties (arch length, arch area, period) depend only on the radius r and are always shown once r is entered.

Formula & Theory - Cycloid Calculator

The Cycloid Calculator uses the standard parametric equations of a cycloid:

Parametric equations:
  x = r(t − sin t)
  y = r(1 − cos t)

One-arch properties:
  Arch length   = 8r
  Arch area     = 3πr²
  Period        = 2πr
SymbolMeaning
rRadius of the rolling circle
tParameter (rotation angle of the rolling circle, in radians)
x, yCoordinates of a point on the cycloid

The remarkable fact that the arch length equals exactly 8r was first proved by Christopher Wren in 1658. The arch area of 3πr² is exactly three times the area of the generating circle (πr²). The period 2πr is simply the circumference of the rolling circle — the horizontal distance traveled in one full revolution.

Assumptions and Limits

The cycloid equations describe the standard (prolate/curtate variants are not supported). The parameter t can be any real number, producing an infinitely extended cycloid. The arch properties computed here correspond to one complete arch (0 ≤ t ≤ 2π).

Use Cases for Cycloid Calculator

The Cycloid Calculator is useful for students and professionals studying parametric curves and classical geometry. Common uses include:

  • Calculus coursework — Verify arc-length and area integrals for parametric curves as a worked example.
  • Physics — The cycloid is the brachistochrone curve (path of fastest descent) and the tautochrone curve; understanding its geometry is essential in classical mechanics.
  • Engineering — Cycloid gear profiles reduce friction and improve load distribution in gear systems.
  • Mathematical exploration — Visualize how x and y coordinates change as t varies and understand the relationship between the rolling motion and the curve shape.

The Cycloid Calculator provides a quick way to obtain accurate numerical values for cycloid coordinates and properties without manual integration or complex derivation.

Frequently asked questions about Cycloid Calculator

What is a cycloid?

A cycloid is the curve traced by a point on the rim of a circle rolling without slipping along a straight line. It is a classic curve in mathematics with elegant area and arc-length properties.

How accurate is the Cycloid Calculator?

The Cycloid Calculator uses standard double-precision arithmetic, providing about 15 significant digits of accuracy for typical inputs.

What is the parameter t in the cycloid equations?

The parameter t is the angle (in radians) through which the rolling circle has rotated. One complete arch corresponds to t going from 0 to 2π.

Is my data stored?

No. All calculations happen in your browser; nothing is sent to a server.