Crochet hat size chart: head sizes from newborn to adult

Head circumference for crochet hats

Hat for	Head circumference on hat charts	In centimeters	Heads measured at that age
preemie	9 to 13 in	23 to 33 cm	no figure here
newborn	13 to 14.5 in	33 to 37 cm	12.4 to 15.3 in (31 to 39 cm), at birth
3 to 6 months	14 to 17 in	36 to 43 cm	14.6 to 18.1 in (37 to 46 cm), from 3 to 6 months
6 to 12 months	16 to 19 in	41 to 48 cm	15.7 to 19.2 in (40 to 49 cm), from 6 to 12 months
1 to 2 years	17 to 20 in	43 to 51 cm	16.7 to 20.2 in (42 to 51 cm), from 1 to 2 years
toddler	18 to 20 in	46 to 51 cm	17.5 to 20.7 in (45 to 53 cm), from 2 to 3 years
child	17.5 to 20.5 in	44 to 52 cm	no figure here
teen	20 to 22 in	51 to 56 cm	no figure here
woman	21 to 23 in	53 to 58 cm	no figure here
man	22 to 24 in	56 to 61 cm	no figure here

Measure the head if you can. Heads of one age differ by inches.
The second and third columns are what hat size charts say. The charts differ, so each row runs from the smallest to the largest figure they give. Centimeters are worked out from the inches.
The last column is not from hat charts. It is heads as measured for two sets of growth charts, boys and girls together, leaving out the smallest 3 in 100 and the largest 3 in 100. It runs from birth to 3 years, where one of the two sets stops.
The standard chart names its sizes without ages. Its baby size, 14 to 16 in (36 to 41 cm), and its toddler size, 16 to 18 in (41 to 46 cm), are smaller than most heads measured at six months and at two years.

A chart is for when you cannot measure. People of one age have heads of different sizes, so a hat made to a measured head fits better than one made to an age.
To measure, pass a tape around the widest part of the head, across the forehead and above the ears. Keep the tape snug.
Make the hat smaller than the head, so that it stretches to fit and stays on. The sources we read take off 1 to 3 inches (2.5 to 7.6 cm): less for a firm stitch, more for a stretchy one.

What is the head size of an adult for a crochet hat?: Hat charts give 21 to 23 inches (53 to 58 cm) for a woman and 22 to 24 inches (56 to 61 cm) for a man.
How big is a newborn's head?: Hat charts give 13 to 14.5 inches (33 to 37 cm). Heads measured at birth run from 12.4 to 15.3 inches (31 to 39 cm).
How big is a 6 month old's head?: In the growth charts we read, heads at six months run from 15.8 to 18.3 inches (40 to 47 cm). The middle is about 17 inches (43 cm).
How big do I make a hat for a 22 inch head?: About 19 to 21 inches (48 to 53 cm) around: 1 to 3 inches smaller than the head, so that it stretches to fit.

A chart says a baby hat is 14 to 16 inches. Will it fit my baby?: Only while the baby is small. That band, 14 to 16 in (36 to 41 cm), is a size with a name, not an age. Most heads measured at six months are larger: the middle is about 17 inches (43 cm). Measure the baby, or use the row for the baby's age.
How tall should a crochet hat be?: A hat's height runs from the top of the head down to the bottom of the ear. The charts we read measure it in different ways and give different figures, so none is printed here. Measure the head you are making for.
How wide should the crown be before I stop increasing?: The charts we read give crown widths that differ from each other, so none is printed here. Work the increase rounds your pattern gives for its size.

Abbreviations What does this abbreviation in my pattern mean?
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Terms in other languages What is this stitch called in a pattern written in another language?
Hook size for your yarn weight Which hook do I use with this yarn?
Hook size by project What size hook do I use for the thing I am making?
Hook size chart What size is my hook, in millimeters and as a US letter or number?
Steel hook sizes What size is my steel crochet hook in millimeters?
Knitting needle to hook size Which crochet hook is the same size as my knitting needle?
Yarn weight chart What weight is my yarn, and what else is it called?
Thread size chart How thick is this size of crochet thread?
Starting chain calculator How many chains do I start with for this width?
Yarn calculator How much yarn do I need to finish this?
Blanket size chart How big should I make this blanket?
Baby blanket size chart How big should I make a baby blanket?
Scarf size chart How long and how wide do I make a scarf?
Size chart for babies How big are a baby's head and feet at this age?
Headband size chart How long do I make a headband or an ear warmer?
Slipper size chart How long is the foot for this shoe size?
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