I am trying to knit a baby hat. I have size 5 (3.75mm) 16" circular needles and some yarn to match this needle size. All the patterns say to cast on a different amount of stitches. How many do I cast on if I want to make a baby hat for a 6 month old (approx 14"-17")? If I can cast on the right amount and make it the hat the right diameter I know how to take it from there.
Need help with baby hat
Here’s a link to approximate sizes for knitted items including baby hats. For 6-12 month olds, the head circumference is 16-19 inches. The actual hat should be about an inch (they recommend an inch to an inch and one-half) smaller.
The number of sts to cast on depends on the gauge or number of sts per inch that you get with your yarn and needles. See how many sts per inch you get andf multiply that by the circumference of the hat.
So, my hat should be about 5.5" to 6" around? And if I can stitch 8 stitches (loose measure or bunch up the stitches measure?) then I need to cast on about 40 to 48 stitches? I did that and it looks so tiny! I don’t know if it will stretch that much.
For 6 months, the head circumference is about 16 inches so that means the hat should measure about [I]15 inches[/I] around. To make sure you come close to that size, do a gauge swatch and measure the sts/inch across a relaxed part of the center of the swatch.
Not around, but across I think you mean. But 6" across is 12" around so that’s still too small. About 7-7½" across laid flat.
Ah, I see. That makes sense to me now! You are all so helpful. 
I think I need about 120 cast on. I have approx. 8 stitches per inch and I multiplied that by 15 to get 120, right? That seems more like it would fit. This hat is going to take me forever now, though. That’s significantly more stitches than I thought. Can’t wait to see how it turns out!
That sounds right. Good luck with the hat and enjoy knitting it!
The circumference of a circle (hat) is equal to pi (3.14) times the diameter, or distance across.
A hat that is 5" across will be 5 x 3.14, or 15.5", around.
A hat that is 6" across will be 6 x 3.14, or 18.5", around.
A hat that is 7" across will be 7 x 3.14, or 21.75", around.
DCM
indeed.
Actually, I’m not sure it does work that way; a hat flattened out isn’t really a circle, it’s a tube that’s flat. If the hat was on a cylider it would have a different measurement across than when it’s laid flat. If I measure something in the round that’s 10" flat, it really is 20" around, not 31".