Circle Tangent Calculator

About Circle Tangents

  • A tangent line touches the circle at exactly one point
  • The radius is perpendicular to the tangent at the point of tangency
  • Two tangent lines can be drawn from any external point
  • Tangent lines are equal in length from the external point
  • The angle between tangent lines depends on distance from center

Note: The external point must be outside the circle to calculate tangent lines. The distance from the external point to each point of tangency is equal. This calculator uses the point-slope form of a line equation.