Reading inches
US fitted size = head circumference in inches divided by π, rounded to the nearest ⅛. That is the diameter of your head, which is why the label looks nothing like the tape reading.
Inches first
Hat size chart in inches
The same hat sizes chart as the home page, but with head circumference in inches leading every row — for US shoppers who measure in inches, plus every size in centimetres for cross-checking.
| US | UK | Head (inches) | Head (cm) | EU | Letter |
|---|---|---|---|---|---|
| 6 5/8 hat size | 6 1/2 | 20 7/8 | 53.0 | 53 | S |
| 6 3/4 hat size | 6 5/8 | 21 1/4 | 53.9 | 54 | S |
| 6 7/8 hat size | 6 3/4 | 21 5/8 | 54.9 | 55 | S |
| 7 hat size | 6 7/8 | 22 | 55.8 | 56 | M |
| 7 1/8 hat size | 7 | 22 3/8 | 56.8 | 57 | M |
| 7 1/4 hat size | 7 1/8 | 22 3/4 | 57.7 | 58 | L |
| 7 3/8 hat size | 7 1/4 | 23 1/8 | 58.7 | 59 | L |
| 7 1/2 hat size | 7 3/8 | 23 1/2 | 59.6 | 60 | XL |
| 7 5/8 hat size | 7 1/2 | 23 7/8 | 60.6 | 61 | XL |
| 7 3/4 hat size | 7 5/8 | 24 1/4 | 61.5 | 62 | XXL |
| 7 7/8 hat size | 7 3/4 | 24 5/8 | 62.5 | 63 | XXL |
| 8 hat size | 7 7/8 | 25 | 63.5 | 64 | XXL |
| 8 1/8 hat size | 8 | 25 3/8 | 64.5 | 65 | XXL |
| 8 1/4 hat size | 8 1/8 | 25 3/4 | 65.4 | 65 | XXL |
Inches ↔ cm
One inch is 2.54 cm. A 23.5 in head is 59.7 cm — and the EU size is simply that centimetre figure rounded to a whole number.
Bigger picture
Charts differ slightly between makers. Treat this inches table as the accurate baseline and check a brand's own chart for its letter labels.
Inches to fitted sizes, at a glance
The fitted column is a head diameter, not a string length — that is why a 23 1/8 in circumference maps to US 7 3/8 and not to "7 3/8 inches". If a page online tells you to match your real head exactly to the fraction on a fitted cap label, it has mixed the two numbers up. A rough sanity anchor that works anywhere: 21 in ≈ US 6 3/4, 22 in ≈ US 7, 23 in ≈ US 7 3/8, 24 in ≈ US 7 3/4 — each inch of head being roughly two fitted sizes (eighths use π, so count on ~4/5 of an inch per size step).
Working in a fabric that stretches, like crochet or a knit label? Give the stretch a column of its own in the crochet chart. And if the measurement is needed for someone who is not buying a fitted cap, the printable tape page prints an inch rule at true scale so you can check any chart against it.
Inches and hat size FAQs
How many inches is a size 7 hat?
A US fitted size 7 is designed for a head circumference of 22 inches, which is 55.8 cm. The label on the hat is actually the diameter of your head in inches — 22 inches around the head divided by π gives about 7 inches across.
How do I convert hat sizes between inches and centimetres?
Multiply inches by 2.54 to get centimetres, or divide centimetres by 2.54 to get inches. For example, 23 1/8 inches is 58.7 cm. Both columns always sit side by side in the chart above, so no conversion is ever required.
Why do hat size labels use fractions like 7 5/8?
The US fitted system sizes hats in eighth-inch steps of head diameter. 7 5/8 means the hat is cut for a head about 7.625 inches across, measured from ear opening to ear opening across the crown — the same number you see in the chart.
Prefer centimetres? The metric hat size chart leads with cm, or use theconverter to type either unit.