How to Measure Baby Head for Sun Hat? | Nail the Fit

Measure your baby’s head circumference just above the eyebrows and ears, then match it to the hat maker’s sizing chart.

A sun hat that fits correctly stays put during a stroller ride but leaves no red marks on your little one’s forehead. The best part about sizing a baby sun hat: you only need one measurement. Measuring a baby’s head for a sun hat takes about a minute, and getting it right means the hat you buy actually protects their face, neck, and ears from the sun.

Where to Place the Measuring Tape

The tape needs to sit exactly where the hat will rest, not somewhere you guess looks right. Take a soft, flexible measuring tape and wrap it around the widest part of the head. That means placing it just above the eyebrows and ears, then around the fullest part of the back of the head.

Nike’s kids headwear guide gives the same advice, noting you should measure about 1 inch (2.5 cm) above the eyebrows. The tape should feel snug against the head but never tight enough to compress it.

Reading the Number and Choosing a Size

Once the tape is in place, read the number where the end meets the tape. That circumference in inches or centimeters is the number you match to the hat maker’s size chart.

• If the measurement falls between two sizes, choose the larger size.
• If you have no tape handy, wrap a piece of string around the head, mark where it overlaps, then lay it flat against a ruler.
• Measure twice. Babies squirm, and a loose reading will make you buy a hat that’s too big — or skip the measurement on a wiggly day and end up with one that’s too snug.

Common size guidelines for baby sun hats use head circumference targets of roughly 45 cm for 0–6 months, 50 cm for 6–24 months, and 55 cm for 2–4 years. US-friendly baby hat charts list expectations like newborn at 13–14 inches (33–35 cm), 0–3 months at 14–15 inches (35–38 cm), 3–6 months at 15–16 inches (38–41 cm), and 6–12 months at 16–18 inches (41–46 cm). KnitPicks’ hat chart offers similar knitting reference points, listing newborn at 14 inches (36 cm), 3–6 months at 17 inches (43 cm), and 6–12 months at 18 inches (46 cm).

Common Measuring Mistakes to Avoid

Most sizing problems come down to four errors: pulling the tape too tight, measuring too low on the forehead, skipping the ears and back of the head, or writing down a loose reading. Each one pushes the final size in the wrong direction.

Relying only on age is the fifth mistake. Age ranges in sizing charts are rough guides, not precise fit predictions, which is why every reputable chart pairs them with head circumference rather than telling you to buy by birthday alone.

For infants specifically, sewing and craft guides advise measuring twice and using the larger reading in case the tape slipped. A slightly roomy hat beats one that’s too small and ends up perched on top of the head instead of shading it.

How a Baby Sun Hat Should Fit

A properly fitted baby sun hat sits snug enough to stay on during normal movement but loose enough that it never compresses the head or leaves marks on the skin. It should never obstruct your baby’s vision.

Sizing charts are approximate and vary by brand and material. Knit hats stretch; woven sun hats don’t. Craft guides point out that negative ease — a finished hat slightly smaller than the head measurement — matters for knit items, but sun hats generally follow the brand’s own chart more closely.

Ready to shop? Our roundup of the best baby sun hats for summer breaks down top picks by fit, coverage, and budget.

If your baby’s measurement falls between sizes on a specific hat’s chart, sizing up is usually the safer call for a sun hat, since a brim that’s slightly wider means more shade.