Knitting for Babies: Size That Sweet Hat Just Right


Baby hats are a quick and easy knit and make an excellent gift for a new little person in your life (or a donation to your local NICU). And don’t get us started on the cuteness factor, which is Off. The. Hook.

The only hitch with this knit is nailing the size! For one reason, not all babies are born with the exact same size noggin. For another, a baby’s head grows the fastest during the first year, making it tricky to guess what size she’ll be during her first winter.

But don’t let that crush your baby-hat-knitting spirit. Our sizing guide takes the worry and guesswork out of equation. All you need to focus on now is finding the perfect super soft and yummy yarn.

Use These Measurements

The following head-circumference averages are based on average clothing sizes.

  • Preemie 9 inches
  • Newborn 11 inches
  • 0-3 month 13 inches
  • 3-6 month 16 inches
  • 6-9 month 18 inches
  • 12 months 20 inches
  • 24 months-4T 21 inches

Time It Right

A warm, cozy knit cap that fits perfectly in the summer won’t keep baby’s ears warm come winter! Here's how to size a hat based on when the baby is born.

For a baby due in the…

  • Spring Knit a hat in a size 6-9 month to wear this year, or 18-24 month for next year.
  • Summer Knit a hat in a size 3-6 month to wear this year, or 18-24 month for next year.
  • Fall Knit a hat in a size 0-3 or 3-6 month to wear this year, or 24 month for next year.
  • Winter Knit a hat in a size 0-3 or 3-6 to wear this year, or 12 month or 24 month for next year.

Calculate Stitches

Using the above sizing information, here is the formula to determine how many stitches you need to cast on knitting in the round to knit that baby hat size:

Circumference (in inches) x stitches per inch = cast on number

You can use the above formula with any weight of yarn and needle size. Knit until your piece is a ½-inch shorter than the desired hat size. Then bind off by k2tog every five stitches until you have one stitch left on your needles. Finally, pull the yarn through the last loop and weave in the ends to your hat.

Keep in mind: You may need to increase (every two stitches k2tog) or decrease (every 10 stiches k2tog) the number of stitches you need to knit together as a decrease depending on the yarn you're using.

So yes, knitting a baby hat requires a little planning. But when you weigh that against the cuteness quotient, there is no contest: baby hats for the win!

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Knitting for Babies: Size That Sweet Hat Just Right