You'll Need
- A soft, flexible cloth tape measure (the kind tailors use)
- If you don't have one: a piece of string and a regular ruler
- A mirror, ideally
to tool
Reference Chart
Hat Size Conversion Chart
Hat sizing uses three different systems depending on where you're buying. US (fractional inches like 7 1/4), UK (slightly different fractional sizing), European (centimeters direct), and the international S/M/L/XL letter scale. This chart converts between all four and tells you exactly how to measure your head to find the right size.
Adult Hat Size Conversion Chart
Head circumference in inches and centimeters with corresponding US, UK, EU, and letter sizes. Sizes are unisex; women's hats and men's hats use the same head measurements.
| Head Circ. (in) | Head Circ. (cm) | US Size | UK Size | EU Size | Letter |
|---|---|---|---|---|---|
| 21″ | 53 cm | 6 5/8 | 6 1/2 | 53 | XS |
| 21 3/8″ | 54 cm | 6 3/4 | 6 5/8 | 54 | S |
| 21 5/8″ | 55 cm | 6 7/8 | 6 3/4 | 55 | S |
| 22″ | 56 cm | 7 | 6 7/8 | 56 | M |
| 22 3/8″ | 57 cm | 7 1/8 | 7 | 57 | M |
| 22 3/4″ | 58 cm | 7 1/4 | 7 1/8 | 58 | M |
| 23 1/8″ | 59 cm | 7 3/8 | 7 1/4 | 59 | L |
| 23 1/2″ | 60 cm | 7 1/2 | 7 3/8 | 60 | L |
| 23 7/8″ | 61 cm | 7 5/8 | 7 1/2 | 61 | XL |
| 24 1/4″ | 62 cm | 7 3/4 | 7 5/8 | 62 | XL |
| 24 5/8″ | 63 cm | 7 7/8 | 7 3/4 | 63 | XXL |
| 25″ | 64 cm | 8 | 7 7/8 | 64 | XXL |
Conversions vary slightly by manufacturer. Always check the brand's specific chart, particularly for fitted hats with no adjustment range. US sizes increment by 1/8 = 0.39 inches = 1 cm.
Kids & Baby Hat Size Chart
Children's heads grow rapidly. Most retailers organize kids' hats by age, but measure when possible; head sizes vary by child.
| Age | Head Circ. | Size |
|---|---|---|
| Newborn (0–3 mo) | 13–14 in (33–36 cm) | Newborn / 0–3M |
| 3–6 months | 14–16 in (36–41 cm) | 3–6M |
| 6–12 months | 16–17 in (41–43 cm) | 6–12M |
| 12–24 months | 17–18 in (43–46 cm) | 12–24M / Toddler S |
| 2–4 years | 18–19.5 in (46–50 cm) | Toddler M |
| 4–8 years | 19.5–21 in (50–53 cm) | Kids S / M |
| 8–12 years | 21–22 in (53–56 cm) | Kids L / Youth |
| 12+ years | 22+ in (56+ cm) | Adult size range |
How to Measure Your Head for a Hat
The Method
- Stand in front of a mirror
- Place the tape measure around your head where a hat would naturally sit: about 1/8 inch above your eyebrows and just above your ears, around the widest part of your skull
- Keep the tape level all the way around. The back of the tape should be at the same height as the front (just above the eyebrows)
- Pull snug but not tight, with no slack
- Read the measurement in centimeters or inches
- Repeat 2 or 3 times to get a consistent reading
- Use the larger number if results vary
Without a Tape Measure
Wrap a piece of string around your head as described above. Mark where the string overlaps. Lay the string flat against a ruler and measure the distance in inches or centimeters.
If You're Between Sizes
For structured hats (cowboy hats, fedoras, hard-brimmed straw), round up. The hat will mold slightly to your head as you wear it. For soft hats (knit beanies, baseball caps), the exact size matters less because they have stretch. For fitted baseball caps (New Era, etc.), round down 1/8 size if your measurement falls between two values; new caps loosen slightly with wear.
Measuring a Child
Most children won't stand still long enough for an accurate measurement. Try while they're watching TV or distracted. Use a soft tape measure. If they squirm, take a quick snapshot of the position and re-measure later with the tape against the table at the same length.
Hat Sizing Guide
How Hat Sizes Work
US hat sizes are based on head circumference in fractional inches, with each size representing a 1/8 inch (about 1 cm) difference. The number on the hat is the head measurement divided by π, then expressed in 1/8 inch increments. For practical purposes, just use the conversion table above.
European hat sizes are simply head circumference in centimeters. Much more straightforward. A 58 cm hat fits a 58 cm head. The drawback: European sizes increment by 1 cm, slightly less precise than the 1/8 inch (0.32 cm) US sizes.
Fitted vs Adjustable
- Fitted: Made in specific sizes (e.g., 7 1/4). No adjustment. Cleanest appearance, but you must know your size. Examples: New Era 59FIFTY, Stetson cowboy hats, dress hats.
- Snapback: Plastic snap closure in the back, adjustable across a 1.5 to 2 inch range. Common in casual caps.
- Strapback: Leather or fabric strap closure, similar adjustability to snapback.
- Velcro back: Common on cheaper caps. Adjustable across the full size range.
- Flexfit / Stretchfit: Stretchy band in the headband, fits a range. Comes in S/M and L/XL ranges typically.
- Elastic back: Common on dad hats and athletic caps. Stretchy fabric panel in the back.
- One-size knit: Beanies. Stretch fits most adult heads.
How Different Materials Fit
- Wool felt (cowboy hats, fedoras): Stretches with wear. Buy at your exact measured size; the hat will mold to you over weeks of wear.
- Fur felt (premium hats): Same as wool but more so. Stretches noticeably over the first few weeks of wear.
- Straw (panama, raffia): Almost no stretch. Buy your exact size; consider rounding up 1/8 if between sizes.
- Cotton twill (baseball caps, dad hats): Minimal stretch. Buy your exact size.
- Wool / acrylic knit (beanies): Significant stretch. One-size fits most.
- Leather (some hat sweatbands): Shrinks slightly when sweaty/wet, returns when dry. Don't size up for "sweat shrinkage."
How a Hat Should Fit
A properly-fitted hat:
- Sits firmly on your head without sliding or rocking
- Doesn't shift if you tilt your head down 30 degrees or shake gently
- Sits about 1/4 to 1/2 inch above your eyebrows (depending on style)
- Doesn't leave a red mark or pressure ring on your forehead after wearing it 30 minutes
- Allows you to slide one finger easily between the sweatband and your forehead
Adjusting a Hat That's Slightly Off
- Too tight: Use a wooden hat stretcher (cheap on Amazon, $15 to $30). Insert into the hat, expand to slightly larger than your head, leave overnight. Wool felt and straw both stretch this way.
- Too loose: Place a foam hat tape (3M makes a foam sweatband adhesive strip) inside the sweatband. Adds 1/4 to 1/2 inch of effective fit reduction. Or use a small piece of folded tissue paper for a temporary fix.
- Way too loose: Take to a hat shop. They can re-stitch the sweatband to size down by 1/8 to 1/4. Cost is usually $20 to $40.
Brand-Specific Notes
- New Era 59FIFTY: Fitted, true to size. Sizes 6 5/8 through 8.
- Stetson: Premium cowboy and dress hats, true to size in their fractional system. Fur felt stretches slightly.
- Bailey of Hollywood: True to size in US fractional.
- Brixton: S/M/L lettering. M = US 7 to 7 1/4. L = 7 3/8 to 7 1/2.
- Filson: Wool felt, runs true to size; expect slight stretch with wear.
- Carhartt: Generally true to size, slightly larger for beanies.
- Goorin Bros: True to size, but some styles are tagged with European sizes.
Frequently Asked Questions
How do I measure my head for a hat?
Wrap a soft tape measure around your head 1/8 inch above ears and forehead. Keep level, snug but not tight. Use the larger of two readings. Round up if between sizes.
What size hat is a 22 inch head?
Size 7 in US, 56 cm in EU, Medium in S/M/L. Roughly average adult male.
What size hat is a 23 inch head?
Size 7 3/8 in US, 59 cm in EU, Large in S/M/L. Common large adult male size.
What is the average hat size?
Average adult male: 7 1/4 (22 7/8 in / 58 cm). Average female: 7 1/8 (22 3/8 in / 57 cm). Range is roughly 6 3/4 to 8.
What is S/M/L for hats?
S: 6 7/8 to 7. M: 7 1/8 to 7 1/4. L: 7 3/8 to 7 1/2. XL: 7 5/8 to 7 3/4. Varies slightly by brand.
Why do baseball cap sizes use fitted numbers?
Fitted caps come in head-circumference sizes (6 5/8 to 8). Each 1/8 = 0.39 in = 1 cm. Don't stretch much, so accurate measurement matters.
Are hat sizes the same in the US and UK?
Close but not identical. UK runs 1/8 smaller than US. US 7 1/4 = UK 7 1/8.
What's the difference between a fitted cap and a snapback?
Fitted = specific size, no adjustment. Snapback = plastic snaps adjust across a range. Snapbacks are forgiving.
Do hats stretch over time?
Wool and fur felt stretch slightly. Straw and structured caps don't. Knit hats stretch a lot. Leather bands shrink when wet, loosen when dry.
How tight should a hat fit?
Firm enough not to slip, loose enough not to leave a mark after an hour. One finger should fit between sweatband and forehead.
Mini About Us
We built this because every hat brand uses a different sizing system and most charts online get the conversions slightly wrong. We cross-checked against New Era, Stetson, Brixton, and Filson's official charts. This site is a part of the ads4good Network.
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