56
cm
22.05
in
7
US
56
2
56
cm
22.05
in
7
US
56
2
The Hat Size Converter converts US hat sizes to head circumference in centimeters and inches, plus EU/International sizing. Hat sizing can be confusing because the US uses a unique numerical system based on the hat's inner diameter, while the rest of the world uses head circumference in centimeters. This converter bridges both systems so you can shop for hats from any country with confidence.
The US hat sizing system uses numbers from about 6 5/8 to 8, where each size represents the hat's inner diameter in inches. The increments are typically 1/8 inch, corresponding to roughly 1 centimeter in circumference. The most common US hat sizes range from 6 3/4 (54 cm) to 7 3/4 (62 cm).
The European and International system uses head circumference directly in centimeters. EU sizes are simply the centimeter measurement: an EU size 58 fits a head with a 58 cm circumference. This system is straightforward and used by most hat manufacturers outside the US. Some brands also use letter sizing (S, M, L, XL), which covers a range of centimeter measurements.
Key reference points for the US-to-metric conversion are: US 6 3/4 = 54 cm, US 7 = 56 cm, US 7 1/4 = 58 cm, US 7 1/2 = 60 cm, US 7 3/4 = 62 cm. Each quarter-size increment corresponds to approximately 2 centimeters in circumference.
To find your hat size, measure your head circumference with a flexible tape measure positioned about 1 centimeter above your ears and eyebrows, across the widest part of the back of your head. This measurement in centimeters is your EU/International hat size, which can then be converted to US size using this tool.
The conversion uses standard hat industry mappings: US 6 3/4 = 54 cm, US 7 = 56 cm, US 7 1/4 = 58 cm, US 7 1/2 = 60 cm, US 7 3/4 = 62 cm. Letter sizes: S = up to 55 cm, M = 56-57 cm, L = 58-59 cm, XL = 60-61 cm, XXL = 62-63 cm, 3XL = 64+ cm. The letter size output uses 1=S through 6=3XL.
The EU size equals the head circumference in centimeters. The letter size is approximate and varies by brand. Most fitted hats are available in 1/8 size increments (US) or 1 cm increments (EU). For fitted hats, measure carefully; for adjustable hats, aim for the middle of the range.
Inputs
Results
US 7 = 56 cm = M
Inputs
Results
US 7.5 = 60 cm = XL
The average adult head circumference is about 56-58 cm (US 7 to 7 1/4), which corresponds to Medium or Large in letter sizing. Men's heads average slightly larger (57-59 cm) than women's (55-57 cm).
Use a flexible tape measure positioned about 1 cm above your ears and eyebrows, around the widest part of the back of your head. Pull snug but not tight. Measure in centimeters for the most direct size selection.
US hat size 7 corresponds to approximately 56 cm head circumference, which is a Medium in letter sizing.
Yes, somewhat. Fitted hat brands like New Era, Stetson, and Bailey are generally consistent within their own lines, but a size 7 from one brand may fit slightly differently from another. Adjustable hats with snapback or strap closures are more forgiving.
Fitted hats come in specific sizes and must match your head circumference closely. Adjustable hats (snapback, strapback, flex-fit) cover a range of sizes, typically S/M or L/XL, making exact sizing less critical.
Some materials (wool felt, straw) can be stretched slightly using a hat stretcher or steam. Synthetic materials and baseball caps generally cannot be stretched. It is better to buy the correct size than to rely on stretching.
The sizing scale is the same, but women's heads tend to be smaller on average (55-57 cm vs 57-59 cm for men). Many women's fashion hats come in one-size-fits-most with adjustable bands.
S (Small) typically fits 54-55 cm, M (Medium) 56-57 cm, L (Large) 58-59 cm, XL (Extra Large) 60-61 cm. This system is common for casual and athletic hats.
A well-fitting hat sits about 1 cm above the ears, does not leave a red mark on the forehead, and does not blow off in light wind. It should feel snug but comfortable. If it gives you a headache, it is too tight.
Straw and wool hats can shrink with exposure to moisture and heat. Leather hats may shrink slightly with sweat and rain. Cotton baseball caps are the most prone to shrinkage. To prevent shrinkage, avoid machine washing and heat drying.
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