This calculator uses the ellipse latus rectum formula only.

Here, a is the semi-major axis and b is the semi-minor axis, so the implementation rejects inputs that do not describe an ellipse.

Enter the semi-major axis and semi-minor axis of an ellipse. The calculator checks the axes before computing the focal chord length.

1. Enter a and b.
2. Make sure both are positive and that a is at least as large as b.
3. Read the latus rectum from the result card.

For a = 5 and b = 3, LR = 2(3^2)/5 = 3.6.

That is the chord through a focus, perpendicular to the ellipse’s major axis.

The old copy claimed support for parabolas and hyperbolas, but the implementation only handled the ellipse formula. The wording now matches the code.

Blank and malformed inputs are rejected before calculation, and impossible axis orderings are refused instead of producing a misleading number.