# This is how you calculate the right hat size

The temperatures are increasing, it's finally getting warmer! Nevertheless, it is possible that the well-known “April weather” can still surprise us on a few days. Some days can still bring some fresh wind with them. In order to be well prepared for this, we have considered dealing with the **topic of hats**.

Why is wool actually so well suited for this and how do I calculate the right size?

Wool is known for **breathability**, **dirt-repellent** and yet **warming** to be. Another interesting property is the hydrophobic outer shell of wool.

That means it is **water-repellent** to a certain degree. It is said that wool fibers can absorb around 30-35 percent of their own weight in water.

This in turn means that the wool does not feel wet. An additional impregnation is therefore not necessary. Handy right?

Furthermore, you won't have any problems if you get a little warmer and sweat, because the elastic fibers are, as I said, **breathable** and **self-cleaning** **effect** in wool.

In order for your self-knitted or purchased pieces to last as long as possible, it is important that you wash your woolen items either in the **washing machine **with wool detergent in the **wool wash** washes. Alternatively, you can also carefully clean things in the sink with your hand using gentle pressure movements.

## Determine hat size

So you've decided to knit a hat. If you use gradient wool for this, we will link you here to the appropriate blog post so that you know how to process it correctly.

So how do we determine the right hat size? In the following post we are referring more to beanies, i.e. hats that are relatively tight-fitting.

There is a fairly simple formula for this. The only data you need is **your head circumference** or that of the person the hat is for.

## How do I measure correctly?

It's very easy. You measure the head circumference by placing the tape measure horizontally just above the ears and the eyebrows around the head. When measuring, make sure that the measuring tape is tight but not too tight. Then you read off the displayed length. Complete!

If you don't have a tape measure at hand, that's no problem either. To do this, simply take a **non-stretchy** ribbon or cord and then mark with a pen or your fingers. Here you take the point where the band is exactly once around the entire head. Then you can simply measure and read the length with a ruler.

But you should take into account that this method will not be as accurate to the centimeter as if you use a tape measure.

## The formula

The necessary formula to calculate the hat size is as follows:

**Head circumference: 3.14 = diameter of the cap plate**

With this formula you get the **complete** diameter of the cap plate and not the radius. That means you measure almost exactly through the center of the cap from edge to edge.

If you are using a stretchy yarn, we would like to give you a tip that you should pull **one to two centimeters **again. Your hat should then fit comfortably.

Which still makes sense if you take the middle of the two values. However, never fall below the lowest! So you don't have to worry if you don't work to the millimeter. So the hat forgives you for minor mistakes.

If you come within the calculated range with your Bobbel wool and needle size, you don't need to unravel everything again and use a different needle size or yarn so that the measurements fit.

If you are thinking of knitting a smaller hat, for example for a toddler or baby, we would advise against deducting one or two centimeters. With such small amounts, it can make a big difference in the end. The same goes for cotton as it doesn't stretch and the hat could end up being way too tight.

## "I don't know the circumference of my head!"

If you have decided to make someone from your circle of friends and acquaintances happy, measuring the head circumference will of course be a bit difficult. After all, the person shouldn't find out about the surprise. In that case, of course, we can't really help you. The only advice we can give you is to use the **standard measurements** as a guide.

Of course, every head is different, but in a situation like this you unfortunately have no other choice. What can also be helpful is to include the person's **hairstyle**. If the person has very full and curly hair, you can deviate slightly from the standard measurements, since the hair will take up more "space". For someone with a bald head, it can be a smaller size, since the hair also influences the circumference.

## Background: How to use the circle formula correctly

Perhaps you still remember the math class. This was also about circles. In connection with circles, the circle number **π (pronounced “pi”)** is usually used.

In mathematics, it is a number with an infinite number of decimal places. As you may have already noticed, the number 3.14 is sufficient for calculating the cap size.

The **general formula** for calculating the circumference of a circle is:

Two times the radius equals the diameter. You could also write the formula like this:

U = π * D

If you change the formula, you can divide both sides by pi and then you get the diameter:

U : π = D

If we replace the individual letters with our hat example, we get the following well-known formula:

**Head circumference: 3.14 = diameter of the cap plate**

Okay, enough with the math class. So now you know what to look out for if you want to knit a cozy hat from Bobbelwolle or a single-colored yarn in the near future.We hope we were able to help you and if you have any other questions, we are happy to help you at any time

Just contact us here using the contact form.

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