A great-looking hat that doesn’t quite fit is incredibly frustrating. Learning how to measure your hat size is the best way to ensure you buy a hat that fits.
These tips are especially useful for online sellers who want their customers to be happy with their fit the first time. Let’s go through a quick hat measurement method that you can use for yourself or on your Shopify store.
How To Measure Hat Size in 3 Easy Steps

Measuring your hat size is a straightforward process, but getting it right makes all the difference in comfort and fit. These three steps are all you need to get an accurate hat measurement.
1. Get Your Measuring Tools
To measure your hat size easily, you’ll need a soft, flexible tape measure like the kind used in tailoring. If you don’t have one, a ruler or regular tape measure could work, but some string or cord would be much better if you can find any. Even wired headphones or a phone charging cord can be used in a pinch! Make sure whatever you use is flexible enough to wrap around your head comfortably.
2. Measure Your Head’s Circumference
Stand up straight but comfortably, and then wrap the tape, cord, or string around your head where the inner band of the hat will rest. This spot is typically about ½ inch above your eyebrows. Don’t let the tape twist or sag, or it’ll give a larger reading than it should. Make sure it stays flat against your head and level with the ground.
Note or mark the spot where the tape or cord meets itself back at your starting point. If using a tape measure, write down that circumference measurement in inches or centimeters. If you’re using a string or cord, measure the length with a ruler or pocket tape measure.
3. Determine Your Hat Size From the Measurement

Now, you need a conversion size chart to determine your hat size. Find the row with the number closest to your measurement. If you fall in between numbers, always round up to get a comfortable fit.
For example, if your head is 22 1⁄4 inches, you would round up to 22 ⅜, giving you a 7 ⅛ size hat. The same rule applies if you’re using metric measurements. If your head is 57.3 centimeters, that falls between 56.8 and 57.8, so go with 57.8 for a 7 ¼ hat size.
If you’re a math whiz, you may have already figured out how to determine a hat size from a measurement on your own. You can divide the circumference by pi (about 3.14) and round up to the nearest ⅛ inch. This figure provides what your head’s diameter would be if it were a perfect circle. However, most folks prefer to stick to the size conversion chart to avoid mistakes (and math).
Consider Head Shape When Measuring for Hat Size

Different hat styles fit differently depending on head shape. This is especially noticeable with helmet sizing and cowboy hats, which don’t have the flexibility of regular hats. If you have a head shape that differs from the standard oval, certain hats may feel tighter or looser in certain areas.
For example, a head that’s longer from front to back and thinner from ear to ear might feel cramped in a standard hat. In this case, a “long oval” hat will likely be a better fit. If you’re planning on buying a cowboy hat, this will be particularly relevant to you.
- Standard Oval: Fits most people, providing an even, comfortable fit.
- Long Oval: Ideal for people with heads that are longer front-to-back and narrower side-to-side.
- Round Oval: For heads that are wider from ear to ear and shorter from front to back.
If you’re selling, be sure to account for these differences in your Shopify store’s sizing chart so customers can easily measure their heads and choose the right fit.
Use Sizing Charts To Help Perfectly Measure Hat Sizes
Hats can be trickier and more costly to ship than other clothing items. Constant returns because of incorrect sizing can hurt your bottom line and brand reputation. Creating accurate sizing charts for your customers can be tedious, especially if you have a ton of different products.
That’s where the Kiwi Sizing app comes in. Our customizable sizing charts make the process much easier by allowing you to include clear, step-by-step instructions and visual aids for measuring hat sizes. Plus, it simplifies unit conversion for international customers, ensuring that everyone gets the perfect fit.
Contact us today to see how Kiwi Sizing can help you improve your sizing charts.