Since Head to Toe came out, a number of people have asked for tips on adapting the hat patterns in it to fit an adult. If you've ever knitted kids hats I am almost certain that you would have noticed that past the age of 3 or 4 their heads are VERY close in circumference to those of adults. It's pretty amazing because kids heads usually look smaller than ours and this is due to the fact that although the circumference might be the same, their depth is often shallower than that of an adult head. Because of this, if the pattern is written out to accommodate a good range of sizes, the only change you'd have to make is make the hat deeper. Since all of the hat patterns in Head to Toe were beanies, I will only cover the adjustment of a basic beanie in depth.
Each conventional beanie consists of three parts: Brim, Body and Crown. Because a beanie is a fairly close fitting hat with a straight up body, the easiest way to add depth to it is to work extra rounds in its brim and body portions.
Before you commence the knitting, examine the pattern reading through it completely and noting the depth of the brim, whether the body has a pattern on it or not and a number of rounds in each vertical repeat if it does.
The way you add depth to the body will depend on the stitch pattern of the hat.
If the hat is plain, ribbed or has an otherwise short vertical repeat (top left and centre, and bottom right), do the same as you did with the brim, just add a few rounds to the body length until you are happy with its depth. Make sure to end with the correct row of a repeat before starting working on the crown.
If the stitch pattern forms a band around the hat (such as the colourwork pattern below), add the extra rounds before and after it, distributing any added rounds evenly.
If the hat has a very long pattern repeat (such as in the bottom left or the top right photos), make a wider brim instead of adjusting its body.