Easily Draw Perfect Ellipses with One Equation
Follow these directions to draw a perfect ellipse in a few minutes with a simple equation and some string.
To draw a perfect ellipse, you need two push pins, non-stretching string, a pencil and a simple formula to determine the distance (D) between the push pins.
Perfect ellipse formula
The formula is D = square root of (L2 – H2). L and H are the length and height of the desired ellipse. Let’s say I want an ellipse 16 in. long by 10 in. high. Plug the numbers into the formula, and you get D = 12-1/2.
Draw a straight line exactly 16 in. long and mark the center point. Mark 6-1/4 in. both directions from the center point, creating the foci and giving you the 12-1/2 in. distance you calculated. Push in a pin at each point.
Make a string loop using a slip knot so you can adjust the loop’s size. Put the loop around the pins. Adjust the loop’s size until a pencil inserted in the loop is exactly at the end of the line. Tighten the knot and draw your ellipse by pulling the loop around the pins with your pencil. – Kellen Johnson