Alternately, if you have your circumference of the head you are trying to make a hat for you can type it into this handy-dandy online calculator I found. Or if you have made your increasing rows in your crown and wonder how big the hat will be you can type in that info. Or if you are old school and just enjoy using a paper in pencil (in which case I suggest you seek medical attention) there is always the C=πD where the c stands for circumference and d stands for diameter. Clear as mud?
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