Crochet Hat Sizes

Have you ever tried to make a handmade beanie for someone but you have no idea how big to make it? I’ve definitely been there! I used to try Googling beanie sizes by age, but one huge problem I kept running into is that every article and sizing chart seemed to have different measurements! And unless you have an actual head to measure, that can be pretty confusing.

This post includes average head sizes, hat measurements with stretch allowance, hat height measurements, and flat circle diameter measurements.

Average Head Sizes and Hat Sizes

For each of these average head sizes, I have included a hat measurement that you should be aiming for when you crochet or knit your beanies. Each hat measurement allows for 2 inches of negative ease. This difference in size takes into consideration how much the hat is going to stretch from being worn. If you make your hate the same exact size as the person’s head, the hat may become over-stretched and a little too big over time.

The 2 inch allowance may not be needed in all cases, for instance, if you are using a more stretchy yarn, then you may need to increase your negative allowance to 3 or 4 inches. The opposite is also true, if you are using a yarn that isn’t very stretchy at all, such as a 100% cotton yarn, then you may need to decrease the negative ease to only 1 inch.

I have included the measurements that I use when I am working with Medium Weight (Size 4) and DK Weight (Size 3) acrylic and acrylic blended yarns. I have also included three hat height measurements which will tell you exactly how tall your hat will need to be based on the fit you are looking for in your hat.

***Pro Tip! If you have a head to measure, measure it! That will give you the most accurate measurement 🙂

Each age group of measurements also includes the flat circle diameter measurements. If you are making your hat in the round then you may need the flat circle diameter measurement. The diameter measurement will tell you the size your circle needs to be in order for your hat to be the correct circumference. You can also figure out your own flat circle diameter by taking your hat circumference measurement (with the 2 inch stretch allowance) and dividing by pi (3.14).

For example, if you are making a hat for someone and their head circumference is 24, you will first need to subtract 2 inches for your stretch, negative ease allowance. In this case, your hat measurement needs to be 22 inches in circumference. To figure out your flat circle diameter, you will take 22 and divide it by 3.14, which equals 7 inches. This means that your flat circle needs to measure 7 inches in diameter for your hat circumference to measure 22 inches.

Preemie Average Head Size (Circumference): 12 inches Hat Size (with 2-inch stretch allowance): 10 inches Flat Circle Diameter: 3.18 inches diameter Hat Height (from mid-ear): 4 inches Hat Height (from the bottom of ear): 4.5 inches Hat Height (for slouchy hat): 5 inches

Newborn Average Head Size (Circumference): 14 inches Hat Size (with 2-inch stretch allowance): 12 inches Flat Circle Diameter: 3.82 inches diameter Hat Height (from mid-ear): 4.5 inches Hat Height (from the bottom of ear): 5 inches Hat Height (for slouchy hat): 5.5 inches

0-3 months Average Head Size (Circumference): 16 inches Hat Size (with 2-inch stretch allowance): 14 inches Flat Circle Diameter: 4.46 inches diameter Hat Height (from mid-ear): 5.25 inches Hat Height (from the bottom of ear): 6 inches Hat Height (for slouchy hat): 6.25 inches

3-6 months Average Head Size (Circumference): 17 inches Hat Size (with 2-inch stretch allowance): 15 inches Flat Circle Diameter: 4.78 inches diameter Hat Height (from mid-ear): 5.5 inches Hat Height (from the bottom of ear): 6.25 inches Hat Height (for slouchy hat): 6.75 inches

6-12 months Average Head Size (Circumference): 18 inches Hat Size (with 2-inch stretch allowance): 16 inches Flat Circle Diameter: 5.1 inches diameter Hat Height (from mid-ear): 5.75 inches Hat Height (from the bottom of ear): 6.75 inches Hat Height (for slouchy hat): 7.25 inches

1-3 years Average Head Size (Circumference): 19 inches Hat Size (with 2-inch stretch allowance): 17 inches Flat Circle Diameter: 5.41 inches diameter Hat Height (from mid-ear): 6.25 inches Hat Height (from the bottom of ear): 7 inches Hat Height (for slouchy hat): 7.5 inches

3-5 years Average Head Size (Circumference): 20 inches Hat Size (with 2-inch stretch allowance): 18 inches Flat Circle Diameter: 5.73 inches diameter Hat Height (from mid-ear): 6.5 inches Hat Height (from the bottom of ear): 7.5 inches Hat Height (for slouchy hat): 8 inches

6-10 years Average Head Size (Circumference): 21 inches Hat Size (with 2-inch stretch allowance): 19 inches Flat Circle Diameter: 6.05 inches diameter Hat Height (from mid-ear): 7 inches Hat Height (from the bottom of ear): 8 inches Hat Height (for slouchy hat): 9 inches

Adult Small (Teen) Average Head Size (Circumference): 22 inches Hat Size (with 2-inch stretch allowance): 20 inches Flat Circle Diameter: 6.37 inches diameter Hat Height (from mid-ear): 7.25 inches Hat Height (from the bottom of ear): 8.25 inches Hat Height (for slouchy hat): 10 inches

Adult Medium Average Head Size (Circumference): 23 inches Hat Size (with 2-inch stretch allowance): 21 inches Flat Circle Diameter: 6.69 inches diameter Hat Height (from mid-ear): 7.5 inches Hat Height (from the bottom of ear): 8.75 inches Hat Height (for slouchy hat): 11 inches

Adult Large Average Head Size (Circumference): 24 inches Hat Size (with 2-inch stretch allowance): 22 inches Flat Circle Diameter: 7 inches diameter Hat Height (from mid-ear): 7.75 inches Hat Height (from the bottom of ear): 9 inches Hat Height (for slouchy hat): 12 inches

Happy Crocheting!