Hat Size Chart: How to Measure Your Head for a Hat, Liner or Sweatband

Every sewn-to-size sweatband, every liner cut to a crown and every custom logo order starts with one number: the head circumference. Here is how to measure it properly, the chart that turns it into a hat size, and what to do when the hat has lost its band and you have nothing to measure.

How to measure a head

Take a soft tape measure and wrap it around the head where the hat will sit: about a finger width above the ears and across the middle of the forehead. Keep it level and snug but not tight. Read the number in inches or centimetres, then measure a second time to be sure. If the reading falls between two sizes, go up; a hat that is slightly loose can be padded with a foam sizing strip, a hat that is too small cannot be fixed.

Hat size chart

Head circumference, US hat size and the letter size most caps use:

21 1/8 in, 53.7 cm: size 6 3/4, Small

21 1/2 in, 54.6 cm: size 6 7/8, Small

21 7/8 in, 55.6 cm: size 7, Medium

22 1/4 in, 56.5 cm: size 7 1/8, Medium

22 5/8 in, 57.5 cm: size 7 1/4, Large

23 in, 58.4 cm: size 7 3/8, Large

23 1/2 in, 59.7 cm: size 7 1/2, XL

23 7/8 in, 60.6 cm: size 7 5/8, XL

24 1/4 in, 61.6 cm: size 7 3/4, XXL

24 5/8 in, 62.5 cm: size 7 7/8, XXL

25 in, 63.5 cm: size 8, XXXL

The US hat size is simply the circumference in inches divided by 3.14, so a 22 inch head is a size 7. UK sizes run one eighth smaller than US sizes, so a US 7 1/8 is a UK 7.

How to measure a hat instead of a head

When a hat comes to the bench with its sweatband torn out, measure the inside of the crown at the base, where the band was stitched. Run the tape around the inside edge and read the circumference. That figure is the length the new band must be once its ends are joined, and it is the size to give us when ordering a sewn-to-size leather sweatband. A stock band of about 25 inches can be cut and joined to fit sizes from 6 7/8 to about 7 5/8, and our XXXL length covers 7 3/4 and up.

Sizing a hat liner

A satin hat liner does not carry the fit, the sweatband does, so a liner needs less precision. Measure the inside crown height from the base to the top of the tip, and the crown circumference, and choose the liner size that matches or is slightly larger; the liner is gathered or tipped at the top and takes up the difference. Our satin hat liners come in several sizes and the size guide on each listing tells you which one fits which crown.

Common mistakes

Measuring over thick hair pulled up in a bun and then wearing the hat with hair down. Pulling the tape tight, which loses about half a size. Measuring the outside of the hat instead of the inside; felt and straw add a full size. And trusting the size printed on an old hat: sweatbands stretch and hats shrink with steam, so a twenty year old size 7 3/8 fedora often measures a 7 1/4 today.

Ready to order

With the number in hand you can order leather sweatbands sewn to your exact hat size, choose a satin hat liner for the crown, or send us both figures with a custom logo liner order. If you are unsure between two sizes, write both in the order notes and we will advise before anything is cut. Ten thousand orders and more than 2,500 reviews at 4.9 stars on Etsy, most of them about fit, are the best proof we can offer that measuring this way works. If the measurement says your hat is only a half size out, the fit guide explains whether to stretch it, pad it or refit the band. For the second number a liner needs, see how to measure a hat crown for a liner.

What size hat liner should I order?

This is the question that stops more people ordering than anything else, so here is the short answer first. If you are ordering one size, order 58 cm, which is US 7 1/4. It covers more hats than any other single size. It is the correct fit for medium and large hats, and it will still go into a small hat, where the extra simply takes up as a little fullness behind the sweatband.

The reason bigger is the safe direction is that a liner is not stretched across the crown like a drum skin. It hangs inside it, and its bottom edge tucks behind the sweatband, which is where all the spare material disappears. So the two errors are not equal. A liner slightly too big still fits: the extra gathers behind the band where nobody sees it, and at worst it sits a shade less crisply. A liner that is too small does not reach the sweatband at all, so it pulls against the crown, works loose and lifts away the first time the hat is knocked. Going up costs you a little neatness. Going down costs you the liner. When you are between sizes, go up.

If you want proper coverage rather than one size, hold three: 56 cm (US 7) medium, 58 cm (US 7 1/4) large and 60 cm (US 7 1/2) extra large. Those three take in the great majority of hats that come across a counter. Add 54 cm and 62 cm only once you know you see the small and the very large regularly, because those two tend to sit in the drawer.

The sizes on our listings

Every liner listing shows the size in both systems with the size name: 6 3/4 (54 cm) SMALL, 7 (56 cm) MEDIUM, 7 1/4 (58 cm) LARGE, 7 1/2 (60 cm) XL and 7 3/4 (62 cm) XXL, with some styles running to 8 (64 cm). The centimetre figure is the head size the liner is meant for, so it lines up with the way hats are sized rather than with the physical width of the satin.

A shop is stocking for hats it has not seen yet, so depth matters more than range. Hold the three core sizes deep and the outliers shallow, and lean the depth towards 58 cm.

Measuring the crown: the second number

Circumference decides whether the liner reaches the sweatband. Crown depth decides whether it sits flat against the top or bunches. To measure depth, lay the tape from the bottom of the sweatband straight up to the inside of the crown top, following the felt.

Typical depths: a fedora or trilby measures 4 to 4.75 inches (10 to 12 cm); a western hat 4.5 to 5.5 inches; a bowler or homburg 4 to 4.5; a cloche about 4; a pork pie 3 to 3.5; and a flat cap or newsboy under 3. Our satin liners are about 4.75 inches (12 cm) tall, which is why they suit the fedora, western and homburg group as they are.

Reading the depth is simple. At 4 inches or more the liner goes in as it is. Between 3 and 4 inches the liner is taller than the hat: fold the bottom edge in once so it sits lower, or trim the top seam and re-gather it. Under 3 inches, skip a gathered liner and line the crown with a flat satin panel instead.

A tall western crown or a top hat is deeper than the liner, and that is fine: the liner covers the top and upper sides, and the lower inside stays bare felt behind the sweatband where nobody looks. One thing to watch: an open-crown western hat measures deeper than the same hat once it is creased, so measure after the crease.

If the hat has lost its sweatband there is nothing for the liner to tuck behind. Measure the circumference first, order the band to that size, fit the band, then the liner.

Big sizes: 7 3/4, 7 7/8 and 8

These are the sizes most shops do not stock, which is why a big head ends up with a hat that fits badly or a hat that fits well with the wrong band inside. The felt is not the problem; a hat can be blocked to any size. The parts inside are. A size 7 3/4 hat has an inside circumference of about 24 3/8 inches (62 cm), a 7 7/8 about 24 3/4 inches (63 cm), and a size 8 about 25 1/8 inches (64 cm). In the UK system those are 7 5/8, 7 3/4 and 7 7/8; in Europe they are simply 62, 63 and 64.

A stock leather sweatband is cut longer than the crown so the ends overlap at the back, and the reed inside the top edge is joined with one ferrule. Our stock band is 25 inches (63.5 cm), which cut and joined covers 6 7/8 up to about 7 5/8. Past that there is not enough leather to close the ring with an overlap, and a band joined end to end without one pulls apart on the first hot day. Stretching a shorter band is not an answer either: sheepskin gives a little, but a band stretched to fit goes back to its length and takes the hat with it.

For 7 3/4 and up we make the band longer. The XXXL leather sweatband is 26.4 to 26.8 inches (67 to 68 cm), reeded like every band we sell, and it closes a 7 3/4, 7 7/8 or 8 crown with the same overlap a stock band gives a size 7. Liners are less of a problem at the top end, because a liner fits by crown height rather than circumference, so most sit in a 7 3/4 or 7 7/8 crown without any change.

Small hats and children's hats

The smallest liner we list is 6 3/4 (54 cm), and the rule for a smaller head is the same rule as everywhere else: order the smallest size and let the extra disappear behind the band. In a hat two or three centimetres smaller than the liner, the spare simply gathers where nobody sees it. Never order a liner smaller than the hat, because then it will not reach the band at all.

Below about 50 cm a 54 cm liner starts to be genuinely bulky rather than merely generous. At that point stop tucking and start sewing: turn the bottom edge under, ease the fullness evenly around the inside as you go, and stitch it to the ribbon with small stitches. You are taking the liner in as you attach it, and on a hat that small the gathers sit deep enough that they never show. The same approach works for a beret or any soft hat with no sweatband to hide the edge behind.

Most children's hats have a cloth band or a grosgrain ribbon rather than leather, and that is usually right: leather is heavier than a light straw needs. Dark colours hide the marks a child will put inside a hat, though a small hat is also the one place where a loud lining is fun rather than foolish.

Hat too tight or too loose?

A hat fits at the sweatband. The felt or straw above it is shaped over a block and does not stretch or shrink usefully on its own, and the satin liner higher up in the crown does not touch the head and has no effect on size at all. So every honest fix is a change to the sweatband: its length, its thickness, or what sits between it and your head.

Hat sizes run in eighths of an inch, about 3 mm of head circumference each. That is why a hat that feels wrong is usually only a half size out, and why the fixes below are all small. If you are more than one size out, no trick will make the hat fit.

Too tight, what works: wear it in, because sheepskin softens and gives a few millimetres in the first weeks, especially in warm weather. Stretch it properly with a two-piece wooden hat stretcher, set a quarter turn past snug and left overnight, repeated once; a little steam over a kettle first lets a felt hat relax with the band. Replace a hard, cracked band with a new supple one of the same size, which often gains the few millimetres you needed because new leather sits closer to the felt. Or fit a band one size longer, since the felt usually has more room than the old band was using.

Too tight, what does not work: wetting the hat and wearing it while it dries stretches the felt unevenly and leaves tide marks. Blowing hot air into the crown with a hair dryer cracks the leather. Cutting the sweatband at the back join and leaving a gap fixes the pressure and ruins the band, because the reed inside no longer holds the shape and the ends fray.

Too loose, what works: self-adhesive foam sizing tape goes behind the sweatband, at the back for a half size or all the way round for a full size. It compresses over time and needs replacing every season or two. We do not sell it; any hat shop does. Folded tissue or a strip of felt behind the band does the same job for an evening and costs nothing, which is the old hatter's trick for a customer between sizes. The permanent fix is a shorter band.