Baby Hat Sizing: How to Measure and Choose the Right Fit

Quick answer

Measure your baby's head at its widest point, just above the ears and eyebrows, with a soft tape. If the measurement falls between two sizes, size up for growth and a gentler fit. Recheck every few weeks because infant heads grow quickly.

A hat that slips over the eyes or leaves red marks is usually a sizing problem, not a stubborn baby. The fix is a quick measurement and a fit check, not a drawer full of guesses.

This guide walks you through measuring your baby's head, reading a hat size chart, and testing the fit at home. It also covers the details that matter for newborns, sun hats, and winter hats.

Why hat sizing is different for babies

Baby heads grow fast in the first year, and a hat that fit last month may already be snug. Unlike adult hats, baby hats are often sized by age range, but age is only a rough guide. Two babies the same age can have very different head circumferences.

A well-fitting hat sits low enough to cover the ears without pressing on the forehead. It should stay put during tummy time or a stroller ride, but you should still be able to slide a finger under the brim. If you cannot, the hat is too tight.

Fabric matters too. Stretchy knits and muslin give you more leeway, while woven cotton or lined hats have less give. When a hat has no adjustable closure, the measurement is your only guide, so take it seriously.

• Check the hat's material before relying on age sizing; stretchy fabrics forgive a half-inch difference.
• Avoid hats with tight elastic bands around the head; they can leave marks and feel uncomfortable.

How to measure your baby's head

Use a soft measuring tape, the kind used for sewing. If you do not have one, use a piece of string or ribbon and then measure that against a ruler. A stiff tape or a metal tape measure will not wrap smoothly and can give a false reading.

Place the tape around the head at the widest point: about an inch above the eyebrows in front and around the widest part of the back of the head. Keep the tape level all the way around, not tilted. Snug it gently so it touches the skin but does not indent it.

Write down the measurement in inches or centimeters and note the date. If your baby is squirmy, measure while they are feeding or distracted. Take two measurements a minute apart; if they differ, use the larger one.

• Measure in front of a mirror or have another adult help keep the tape level.
• Record the date so you can track growth and know when to remeasure.

Reading a baby hat size chart

Most baby hat size charts list a head circumference range for each size, often alongside an approximate age. Trust the circumference range first. For example, a chart might list newborn as 13–14 inches, 0–3 months as 14–16 inches, and so on. If your baby measures 15 inches, the 0–3 month size is the better starting point even if your baby is only 6 weeks old.

If the measurement falls exactly on the boundary between two sizes, choose the larger size for room to grow, unless the hat is for a special occasion and you need a snug look. A slightly loose hat can be worn now and will still fit next month.

Some hats are listed as one-size or age-based only, with no circumference range. In that case, look for adjustable features like ties, snaps, or a soft brim you can fold. If the product page gives no measurements at all, treat it as a limitation and consider a different style.

• Always check the size chart on the product page; do not assume a brand's 0–3 month is the same as another's.
• For sun hats, a chin strap or adjustable toggle helps keep the hat on in the stroller.

Testing the fit at home

Once the hat arrives, try it on before washing. It should slide on easily over the head without rolling up or catching the ears. The brim should sit just above the eyebrows, not covering them. If the hat covers the eyes, it is either too big or the wrong shape for your baby's head.

Check for pressure points after a few minutes of wear. Look for red marks on the forehead or behind the ears. A hat that leaves deep marks is too tight, even if it stays on. A hat that slides off with a gentle shake is too loose and may not stay on outdoors.

For winter hats, make sure the hat covers the ears but does not block hearing completely. For sun hats, a wide brim is useful, but it should not flop down over the eyes. If the hat has ties, tie them loosely under the chin and never around the neck.

• Do the two-finger test: you should be able to slide two fingers under the brim at the forehead.
• If the hat leaves marks, size up or choose a stretchier fabric.

When to size up and when to wait

Newborns grow out of the smallest hats quickly, sometimes in a few weeks. If you are buying ahead, it is usually better to buy the next size up rather than several newborn hats. A slightly larger hat can be folded or worn with the brim rolled, while a too-small hat is useless.

For older babies and toddlers, head growth slows down, so a well-fitting hat can last a season or more. If your child is between sizes and you need the hat to last through winter, choose the larger size and use the adjustable features if available.

If you are unsure, measure again before ordering. A difference of half an inch can change the size you need, especially in the newborn range.

• Buy one size up for newborns if you want the hat to last more than a month.
• For toddlers, a hat that fits now may still fit next season; check the measurement before replacing it.

Step-by-step hat sizing checklist

1. Measure the head at its widest point: Wrap a soft tape around the head just above the eyebrows and around the widest part of the back. Keep it level and snug, not tight. Write down the number and the date. If you get two different numbers, use the larger one.
2. Compare the measurement to the size chart: Find the circumference range that includes your measurement. Ignore age labels if they conflict with the number. If you are between sizes, size up for growth and comfort.
3. Try the hat on before washing: Slide it on gently. The brim should sit above the eyebrows and cover the ears without pressing. Check for red marks after a few minutes. If it leaves marks, it is too tight. If it slides off with a gentle shake, it is too loose.
4. Remeasure every few weeks: Infant heads grow quickly. A hat that fit at 2 months may be snug by 4 months. Keep a note of the last measurement. When in doubt, measure again before buying a new size.

Products that help with fit and comfort

• Snap Front Footie - Cherry Picking: This snap front footie lets a baby crawl freely with a snug and comfy fit and features fold over mittens in size NB and 0-3m, plus snaps from neck to toe for easy changes. Fold-over mittens protect a newborn's face from scratches, and the full snap opening makes dressing easier when you are also adjusting a hat.
• Muslin Side Snap Kimono - Lavender Stars: Our super soft, organic Egyptian muslin kimono is a long sleeve romper featuring snaps all along the side front from the neck down for easy changing and comfort. Side snaps mean you can dress a baby without pulling anything over the head, which is useful when you are trying to keep a hat in place.

A good baby hat comes down to one number and a quick fit check. Measure at the widest point, follow the circumference range on the size chart, and size up when you are between sizes. Then watch for red marks and remeasure as your baby grows.