Quick question

so I want to make a baby hat. The pattern calls for 45 cast ons. The think is the yarn is really thin and the circular needles are 12’ but I need more cast ons. How many can I cast on to make it work with the pattern. I am think a need twenty some more…

Usually patterns have a gauge listed. If that’s the case, definitely knit a swatch, check your gauge, and it could turn out that you have the right gauge for a 45 stitch cast-on!

Take a look at the weight of the yarn called for in the pattern. It might be that your yarn is a bit smaller in gauge than the yarn called for. Also, I have learned that hats stretch more than you think they will. If you have cast on the right # and the right yarn, I would personally knit for an inch and see if the bottom doesn’t seem to be bigger once you get past the needles.