Knitting 🧶 Knitters

I was wondering, just how many stitches can you cast on with just long straight needles instead of using circular needles?
I am using Number eight circular needles right now. And I have 151 stitches on it, but I would like to go to straight needles if possible.

It depends on the yarn thickness or weight and the length of the needles. More sts in sport weight will fit on a needle than bulky weight.
Depending on the length of your straight needles, you may be able to fit the sts onto them. You could try knitting 25sts onto the straights and see how much length they take up slightly squeezed together. Then multiply that length by 6 to see if your needle will work comfortably.