Why Are Hats Sized in Eighths?
Why are hats sized in eighths? Because fitted hat sizes come from the head’s diameter measured in eighth-inch steps, a convention carried over from traditional hatmaking. That is why fitted sizes read 7, 7 1/8, 7 1/4, 7 3/8, and so on, each an eighth apart. Speedy Pros Hats, family-owned in Brandon, FL since 2009, customizes hats in fitted, cm, and adjustable sizing with a free digital proof.
It looks quirky next to the metric system, but the eighths are just the historical unit of the trade. Each eighth-inch step of diameter works out to about a quarter-inch of circumference, small enough for a precise fit, which is exactly why fitted caps can feel so tailored.
Speedy Pros Hats, a family-owned custom hat company serving the Tampa Bay area, has decorated hundreds of thousands of caps for teams, businesses, and events over more than 15 years. Every hat is decorated here in the USA, any order size is welcome, and free artwork setup is included on orders of 12 or more.
- Sizes come from head diameter. Measured in eighth-inch steps.
- A hatmaking tradition. The trade’s historical unit.
- 7, 7 1/8, 7 1/4, 7 3/8… Each an eighth apart.
- One eighth ? 1/4 in circumference. Fine enough for a precise fit.
Why Are Hats Sized in Eighths?
Fitted hat sizes are based on the head’s diameter, and traditional hatmakers measured that diameter in eighth-inch increments. So a size 7 hat corresponds to a 7-inch diameter, a 7 1/8 to seven-and-an-eighth, and up the scale in eighths. It is a convention from the days of block-and-form hatmaking that simply stuck, which is why fitted sizes still climb in those odd-looking fractions. Our common hat sizes guide lists them.
The eighths line up neatly with circumference. Because circumference is diameter times pi (about 3.14), each eighth-inch step of diameter is roughly a quarter-inch of circumference, so the fitted sizes step up in about quarter-inch circumference increments. That is fine enough to give a genuinely tailored fit, which is part of why a true fitted cap can feel so exact. See hat size vs circumference.
Other systems skipped the eighths. Europe just labels the circumference in whole centimeters, and S/M/L groups ranges, both easier to read but less precise than eighth steps. So the eighths are not the only way; they are the traditional, high-precision way inherited from hatmaking. To find your size in any system, measure your circumference (our measuring guide shows how) and convert.
Eighth Sizes and Circumference
Here is how the eighths map to the head:
| Fitted (diameter-based) | Circumference (in) | Circumference (cm) |
|---|---|---|
| 7 | 22 | 56 |
| 7 1/8 | 22 3/8 | 56.8 |
| 7 1/4 | 22 3/4 | 57.8 |
| 7 3/8 | 23 1/8 | 58.7 |
| 7 1/2 | 23 1/2 | 59.8 |
Fitted sizes rise in eighths of an inch of head diameter, each step about a quarter-inch of circumference, a hatmaking convention that gives a precise fit.
So the eighths come from measuring head diameter the traditional hatmaking way, each step about a quarter-inch of circumference. It is precise, if quirky. We size your caps to whatever format you use.
Does It Matter for Ordering?
For most custom orders, not much, because adjustable and stretch-fit caps cover a range and skip exact sizing entirely. The eighths only matter when you order true fitted caps, where you pick the precise eighth-size for each head. Even then, you just measure your circumference and convert; you never have to think in diameter yourself.
We customize hats in fitted (by the eighth), centimeter, and adjustable sizing in the USA with no minimums and a free digital proof. Browse custom hats or start a custom order.
Sizing and Your Logo
The size system has nothing to do with decoration, a centered embroidered logo sits the same at any size.
For groups, adjustable and stretch-fit caps skip the eighths and cover a range of heads.
We proof your logo and colors before anything is made, whatever sizes you order.
You never have to think in eighths. Just measure your circumference and read a chart, the conversion to the eighth-based fitted size is done for you. The eighths are the trade’s unit, not something you calculate.
When the Eighths Matter
The eighth sizes matter mainly when you order true fitted caps, where each head gets its precise size. For adjustable and stretch-fit caps, you can ignore them, the cap covers a range.
To find and convert your size, our measuring guide and size vs circumference guides help.
How to Order Custom Hats in Any Size
Give us a fitted size, a circumference, or just choose adjustable to cover a range; then send your logo and approve the free digital proof. There are no minimums, with free artwork setup on orders of 12 or more, and every hat is decorated in the USA.
Browse our custom hats, or start a custom order and we will proof it first. Pricing and the production window are shown on the quick order page.
Trying to convert eighths in your head. You do not need to. Measure your circumference and read a chart, the eighth-based fitted size is looked up for you, so there is no mental math to get wrong.
What to Send and What You Get
Send your logo as a vector file when you can — an AI, EPS, or PDF — and we set it up for decoration. A high-resolution PNG works too, and if the art needs cleanup we handle it. Free artwork setup is included on orders of 12 or more, so most orders start with no setup cost at all.
We match your brand colors on the free digital proof, where you see the cap and the logo together before anything is made. Nothing goes into production until you approve that proof, so the first Order hats off the line is the one you signed off on — colors, size, and placement included.
Reordering is simple. Your setup stays on file, so a repeat run comes back consistent with the first. With no minimums you can start with a single piece or a small batch to confirm the look, then scale up once the design is proven, all from the same shop and the same quick order page.
Every order includes that free proof and our help getting the art right, so you are never guessing at the result. If something is off on our end, we make it right or remake the order on a production error — that is the whole point of proofing before production, to catch anything before a hat is made rather than after.
Why Order Custom Hats From Speedy Pros Hats
We are a family-owned custom hat company in Brandon, FL, decorating hats for the Tampa Bay area and customers nationwide since 2009. Over more than 15 years we have stitched hundreds of thousands of caps, and we hold a 4.9 out of 5 rating across more than 23,000 reviews.
Every order is decorated in the USA with no minimums, so you can test one cap or outfit a whole organization. You get a free digital proof before production, and free artwork setup is included on orders of 12 or more. Pricing and the current production window are shown on the quick order page, and if we make a production error, we make it right.
Why are hats sized in eighths?
Because fitted sizes come from the head’s diameter measured in eighth-inch steps, a convention from traditional hatmaking. That is why fitted sizes read 7, 7 1/8, 7 1/4, and so on.
What does a fitted hat size actually measure?
The head’s diameter in inches, so a size 7 corresponds to a 7-inch diameter. Each eighth-inch step is about a quarter-inch of circumference.
Why not just use centimeters?
Some systems do, Europe labels hats in centimeters of circumference. The eighths are the older, more precise hatmaking convention that US fitted sizing kept.
How much bigger is each eighth size?
About a quarter-inch of head circumference per eighth-inch of diameter, small enough to give a precise, tailored fit.
Do I need to understand eighths to order?
No. Measure your circumference and read a chart, the conversion to the eighth-based fitted size is done for you, and adjustable caps skip it entirely.
Are custom hats decorated in the USA?
Yes. We customize hats in fitted, centimeter, and adjustable sizing in the USA with no minimums, a free digital proof, and free artwork setup on orders of 12 or more.
Hats are sized in eighths because fitted sizes come from the head’s diameter in eighth-inch steps, a hatmaking tradition that gives a precise, tailored fit. You never have to do the math, just measure your circumference and convert, and adjustable caps skip the eighths altogether.
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