How To Estimate Size For Crochet Hats



 I do not know where I acquired this information.

I have had it written down in an old notebook for many, many years.

I am posting this with the hope it may help others as it has helped me.

I do not claim to be the author of this information and will gladly remove it if it offends anyone.  This information should not be considered absolute but merely an aid to determine a beginning point when making crochet hats

Newborn

Head Circumference 13" - 14 "

Hat Circumference = 11.5" - 13"

Hat height = 5.5 to 6"

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Baby - 3 to 6 months

Head Circumference: 14" - 17 "

Hat height= 6.5 - 7"

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Baby - 6 to 12 months

Head Circumference: 16" - 19 "

Hat height = 7.5"

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Toddler -12 months - 3 years

Hat height = 8"

Head Circumference: 18" to 20 "

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Child - 3 - 10 years

Hat height =8.5"

Head Circumference: 19" - 20 1/2"

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Teens

Hat height 9-10"

Head Circumference: 20 1/2" - 22"

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Adult Woman

Head Circumference: 21.5" - 22.5"

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Adult Man

Head Circumference: 23" - 24"

There are a few ways to adjust the size of a hat.

1. A larger or smaller hook

2. Adding more stitches to the increase rounds.

3. Yarn weight, baby, worsted or chunky.

You can gauge your individual crochet tension by crocheting a swatch of the chosen yarn in the stitch you will be using.  It should be approximately 4 x 4 inches.  Measure how many rows and how many stitches are in the 4 inches. If you are getting more rows and more stitches in the 4 inch swatch than what the pattern gauge is, that means your hat is going to be to small or tight.

If you follow the pattern materials closely (Hook size, yarn size), your hat should come close to the measurements.

For Children: The head grows to almost 80 per cent of the adult size during the child's first year.  For hat sizing, head measurement is more important than the child's age.

I do not recommend this for young infants, but measuring the head size is not really all that hard.   You can use a sewing tape measure or if you don’t have one of those, use a length of string that you can later measure with a ruler to determine the length. 

Place the string or tape around the head about 1/8 inch above the ear, across the mid-forehead, completely circling the head.  Do not wrap down at an angle toward the base of the neck.  The tape or string should be horizontal (like a desk top) around the head.  Hold the tape firmly, but not too tightly.

As always with size, results depend on the pattern chosen, the crochet tension of the artist as well as the size of the hook and weight of the yarn.  A test swatch is always helpful when size is critical or a concern.

The following link is the best site I have found for explaining how to properly fit a hat, including international size conversions.
She appears to have made a science of it so I hope this will help.

http://anniespictureperfect.blogspot.com/2013/01/how-to-properly-size-crochet-hats-chart.html