[pavasa]

The hat I am crocheting is from Crochet World "Party Time jacket & Hat". It is crocheted as a flat piece then the ends sewn together to form a tube. My scale is correct. The finished head size stated is 18", and though I have added a couple extra rows, the measurement across the flat piece is only 14". Sure looks big enough for a one year old, but I have no way to double check, because granddaughter lives states away, and I need to be sure it will fit this time. The first one I made just following the directions was way too small. Should I just keep adding rows until the width of the piece measures 18" across.
hopefully i have attached correctly so you can see a pic.

 

[pavasa]

Oops!! I said scale when I meant GAUGE is correct.
Pavasa

 

[Hilary4]

There is a chart here that may help you: http://www.woollywormhead.com/sizing/

 

[NCOB]

Thanks for the website. This should be helpful.

 

[Rafiki]

Head Measurement for Hat
The most accurate way to get a custom fit for a hat, is to measure the head, working your modified pattern to a head measurement. If a gauge is available with the pattern, that will also give you an idea on how close your crochet style is to that of the author of the pattern.

The easiest way to change size with a hat pattern is to use a larger or smaller crochet hook. Another way to change size is to eliminate rounds for a smaller hat or do additional rounds with increase stitches for a larger hat.

The following chart is an estimate for various size heads

Newborn
Head Circumference 13" - 14"
Hat Circumference 11.5" - 13"
Diameter 3.66" - 4.14"
Hat height 5.5" - 6"

Baby
Head Circumference 14" - 17"

3 to 6 months
Diameter 4.46" - 5.4"
Hat height 6.5" - 7"

Baby
Head Circumference 16" - 19"

6 to 12 months
Diameter 5.09" - 6.05"
Hat height 7.5"

Toddler
Head Circumference 18" - 20"

12 months to 3 years
Diameter 5.73" - 6.37"
Hat height 8"

Child
Head Circumference 19" - 20.5"

3 to 10 years
Diameter 6.05" - 6.53"
Hat height 8.5"

Teens
Head Circumference 20.5" - 22"
Diameter 6.53"
Hat height 9" - 10"

Adult Woman
Head Circumference 21.5" - 22.5"
Diameter 6.48" - 7.16"

Adult Man
Head Circumference 23" - 24"
Diameter 7.32" - 7.64"