Sauna Hat for Big Heads: How to Measure and What Fits

Here is a fact most hat shoppers never hear: a US hat size is simply your head circumference in inches divided by pi. A 22 1/4 inch head is a size 7 1/8, and a 26 inch (66 cm) head lands at about 8 1/4. If beanies ride up on you or leave a red line on your forehead, this guide shows you how to measure properly and which sauna hat will actually fit.

Key takeaways

1. Fit matters more in the sauna than on the street.
2. Measure your head in two minutes.
3. The Original fits heads up to 26 in (66 cm).
4. From 26.4 in (67 cm), choose the Pro.
5. Lots of hair, locs and braids change the math.
6. Check the fit on the bench.

1. Fit matters more in the sauna than on the street

In a Finnish style sauna the air is hottest up top. A 2018 review in Mayo Clinic Proceedings by Laukkanen, Laukkanen and Kunutsor gives 176 to 212°F (80 to 100°C) at the level of the bather's head as the recommended range, with lower temperatures near the floor. So your head sits in the hottest layer of the room. A sauna hat only does its job when it covers the top of your head and your ears and stays there. A hat that is too small creeps up every time you lean back against the wall, and your ears pop out right when the heat peaks. A hat that is far too big slides over your eyes. Before you pick a model, get one number: your head circumference.

2. Measure your head in two minutes

You can do this yourself. In a 2014 study in Molecular Autism, Sullivan and colleagues had 57 adults measure their own heads twice and compared the results with trained researchers. Agreement between self and researcher was rated acceptable (intraclass correlation 0.84). The group was small and healthy and used fiberglass tapes, so take it as reassurance, not a guarantee. Their method, adapted for hats:

• Use a soft tape that does not stretch. No tape? Use a string or a charging cable, then lay it on a ruler.
• Run it slightly above your eyebrows and above your ears, around the widest part of the back of your head.
• Pull it snug, not tight, and read the number in inches.
• Measure twice. If the numbers differ, use the larger one.

3. The Original fits heads up to 26 in (66 cm)

The Original is one size and fits heads up to 26 in (66 cm). Using the pi rule, that is a US hat size of about 8 1/4, so it covers far more heads than the words one size suggest. It is a single layer of boiled wool, called Wollwalk in German, and it arrives flat. You pull it on and fold the brim up twice. Those folds are how it adapts: on a smaller head you fold deeper, on a larger head you fold less and let more wool cover your head. Rolled tight it looks like a fisherman beanie, and it covers your ears either way. If you measure 25 in or more, start with shallow folds. You can compare both models in our fit guide.

4. From 26.4 in (67 cm), choose the Pro

Above 26 in, the Original runs out of fabric to fold. For heads from 26.4 in (67 cm) we recommend the Pro. It has a roomier cut, a double layer of boiled wool, extended ear protection and a sewn brim over the forehead and eyes. It needs no folding because it keeps its shape, which makes it simple for big heads: put it on and you are done. If you land between 26 and 26.4 in, the Original will sit snug. If you like a close fit, that can work. If you want room to spare, or you like very hot rounds on the top bench, the Pro is the calmer choice. In the US, the Pro comes in Stone.

5. Lots of hair, locs and braids change the math

Hair counts. A bun, locs or a full set of braids tucked up can add a surprising amount to the number on the tape. So measure the way you will wear your hair in the sauna: gathered, tucked and loose enough to be comfortable. If that number is over 26 in, or your hair simply takes up a lot of room, go for the Pro, which we recommend for lots of hair and dreadlocks. Comfort matters here too. The American Academy of Dermatology advises against hairstyles that pull, recommends pulling hair back loosely under head coverings, and lists coverings that rub constantly over tightly pulled hair as a source of strain. A hat that rests on your hair instead of squeezing it is the goal.

6. Check the fit on the bench

A good fit is easy to recognize after one round:

• The hat covers the top of your head and both ears.
• It does not press a line into your forehead after ten minutes.
• It stays put when you lean back against the wall.
• You can slide a finger under the edge without effort.

If the Original keeps creeping up, unfold one turn of the brim. If it still rides up, you are probably in Pro territory. Wool can feel warm at first, so many people dip the hat in cold water and wring it out well before the first round. More tips are in how to wear a sauna hat.

FAQ

What hat size is a 24 inch head?

About 7 5/8 in US sizing. Divide your head circumference in inches by 3.14 and round to the nearest eighth. A 24 inch head fits the Original with room to fold the brim.

Can I wear a sauna hat over dreadlocks?

Yes. Measure with your locs gathered the way you will wear them in the sauna. If your hair takes up a lot of room or the number is over 26 in, the Pro with its roomier cut is the better choice.

Does a one size sauna hat fit a big head?

The Original fits up to 26 in (66 cm) because you adjust it by folding the brim. Beyond that, from 26.4 in (67 cm), the Pro gives you the room you need without any folding.

Ready to pick yours? See all hats and colors, and if you have long or colored hair, read how to protect your hair in the sauna.