Crocheting hats is something I know well. In my experience, getting the hat to fit properly without a model is not always easy. Most Beanies start of with a flat circle. The size of the circle depends upon the circumference of the head. Looking on the Internet I have found several Blogs that offered a chart    to help in getting the proper size. The measurements for the circumference of the head and the corresponding sizing for the flat circle and hat height varied somewhat. Purchasing patterns can add to the frustration. I have had great differences for the same size between different designers. To take the mystery out of fitting my hats, I started to keep a chart for the sizes I made the most. This was very helpful. I also did a lot of research into how to correctly size your flat circle and height of the hat. I found a formula that helps in getting the correct size. To figure out the diameter of your flat circle all you need to know is the circumference of the head. An adult woman's head averages about 22 inches. The formula is to divide your circumference by 3.14. Head circumference 22 : 3.14 = 7.00 inches. Now you know your circle needs to be 7 inches. To get the correct height (from top of crown to bottom of the ear) you divide your circumference by 10 and multiply this number times 4. Head circumference 22 : 10 = 2.2 x 4 = 8.8. So the hat height should be 8.8 inches. Hats are generally made about an inch smaller in circumference than the circumference of the head. This keeps the hat fitting snug and to keeps it from falling off. Most patterns generally have about an inch stretch to them.  I am going to post the chart I made for myself. This is the chart I use to size the hats I make. It is a good reference and I hope it helps.   Size Head Circumference Hat Circumference Crown Circle Diameter Hat Height -Top of Crown to Bottom of Ear Preemie 1 – 2 pounds 9 – 10 inches/23 – 25 cm 7.5 – 8 inches/18 – 20 cm 1.75 – 2 inches/4 ½ – 5 cm 3 – 3.5 inches/ 8 – 9 1/2 cm Preemie 2 – 3 pounds 10 – 11 ¼ inches/25 – 28 cm 8 1/2 – 10 inches/22 – 25 cm 2.0 – 2.25 inches/5 cm 3.5 inches/9 – 9 ½ cm Preemie 4 – 5 pounds 11 ½ – 12 inches/28 – 30 cm 9 – 10 inches/23 – 25 cm 2.5 – 3 inches/ 6 ½ – 8 cm 3.5 – 4 inches/9 – 10 ½ cm Preemie 5 ½ – 6 pounds 12 – 13 inches/30 – 33 cm 10 - 11 inches/25 – 28 cm 3.0 – 3.5 inches/7 ½ – 9 cm 4 – 4.5 inches/10 ½ – 11 ½ cm Newborn 13 inches/33 cm 12 – 12.5 inches/30.5 – 32 cm 3.5 – 4.0 inches/9 – 10 ½ cm 4.5 – 5.5 inches/11 ½ – 14 cm 2 weeks – 3 months 14 inches/35.5 cm 13 – 13.5 inches/33 – 34.5 cm 4.45 – 4.75 inches/11-12.5 cm 5.5 – 6 inches/14 – 15 ½ cm 3 – 6 months 15 inches/36 cm 14 – 14.5 inches/35.5 – 37 cm 5 inches/ 13 cm 6 – 6.25 inches/15 ½ – 16 cm 6 – 9 months 16 inches/40.5 cm 15inches/36 cm 5.25 inches/14 cm 6.25 – 6.5 inches/16 – 16 ½ cm 9 -12 months 16.5 inches/42 cm 15.5 inches/ 39.5 cm 5.25 – 5.5 inches/14 – 15 cm 6.5 inches/16 ½ cm 12-18 months 17 inches/43.5 cm 16 inches/ 40.5 cm 5.5 - 5.75 inches/15 cm 6.75 inches/ 17 ½ cm 18-24 months 18 inches/46 cm 17 inches/ 43.5 cm 5.75 – 6 inches/15 – 16 cm 7.25 inches/19 cm 2-5 years 18 – 19 inches/46 – 48.5 cm 17 – 18 inches/43.5 – 46 cm 6 – 6.25/16 cm 7.25 – 7.5 inches/ 19 cm Child 19 – 20 inches/48.5 – 51 cm 18 – 19 inches/46 – 48.5 cm 6.25 – 6.5 inches/16 cm – 17 cm 7.75 – 8.0 inches/20 cm Teen 20 – 21 inches/51 – 53.5 cm 19 – 20 inches/48.5 – 51 cm 6.5 – 6.75 inches/17 8.0 – 8.5 inches/20 – 22 cm Adult Woman 22 inches/56 cm 21 inches/53.5 cm 7 – 7.5 inches/18 – 19 cm 8.75 – 9 inches/23 cm Adult Man 23 inches/ 59 cm 22 inches/56 cm 7.5 - 8 inches/19 – 20 cm 9.25 – 9.50/23 ½ cm My next post will show this formula in action. I have already completed the hat and taken some photos but still need to write the post. Stay tuned and have those crochet hooks ready! See you in a couple of days.