From a Circle to an Oval

Dear crochet experts,

can you imagine a ratio where I start with a circle (about 40 single crochet stitches) and end with an oval (about 100 single crochet stitches)???

And for those wondering why I don’t just start with an oval right away... I’d like to have a round base and an oval “opening.”

Thanks in advance

I'm not sure if I understood it correctly, but maybe it could work like this: first crochet the circle to the desired size, then continue another quarter with single crochet, make a transition with half stitches, then a few double crochet stitches. And then work back to the halfway point again, and do the same on the other side. 

That's how I sometimes crochet the shape of eyes. 

I really like doing this with my figures, too—starting with a circle but ending up with an oval shape. To do this, you just have to “shift” the increases to the edge. For example: for a ring with 12 sc,

3 sc, (inc)x3, 3 sc, (inc)x3, etc., etc.—just always leave the 3 sc in between. This pushes the increases to the edge and creates an oval shape. In between, crochet a round of just sc every so often so it doesn’t ripple

Best wishes, Yazzie