Sizing Bottom Up Hats – How To Use Any Sizing Chart!

Sizing Bottom Up Hats

They’re fast and fun to create, but many Hat Sizing Charts are not designed for them. Here is how you can use any Hat Sizing Chart to your advantage and soon be correctly sizing bottom up hats the first time, every time! To see my post on how to use this chart for top down hats click here:


You can use any sizing chart you like, but here is my Hat Sizing Chart for easy reference:


Finding Your Gauge

The first thing you need to do when sizing bottom up hats correctly is determine the gauge you are working at. Take the yarn and the needles or hook you plan to use and work a square which is about 3×3 inches. Take a tape measure and count how many stitches are in 2 inches of your square and divide that number by two. This will be the number of stitches you need per inch to cast on or chain when you start your brim. Don’t worry if it’s not a whole number.


Getting Started

Next take a look at the Hat Circumference section for the size you desire and multiply that number by your “stitches per inch” number.

For example: Let’s say I do my gauge and I have 12 stitches in 2 inches. I divide that by 2 and get 6 stitches per inch. I decide I want to make a hat for 0-3 Months so I multiply 6 by 12.5 which equals 75. So now I know I need to start with 75 stitches. If your final cast on/beginning chain number isn’t whole, simply round up or down to the next whole number.

If you want to have a ribbed pattern which requires a certain number of stitches for each ribbing repeat, simply round up or down to the next closest appropriate number for your ribbing. For example: My calculations show I need to start with 75 stitches, but let’s say I wanted to have a k2, p2 ribbing at the bottom of my hat. This is a 4 stitch repeat so I need to find the multiple of 4 which comes closest to 75. After fiddling with my calculator for a second I see that 4 x 19 = 76. This number will work perfectly for my sizing and ribbing!


Hat Length

The next thing I need to know is how long I should work evenly before beginning the decreases for the crown of the hat. For that I would look at the Hat Height section. Since the chart was designed for hats that are worked from the top down, the Hat Height measurement was calculated to include the crown length. Since you are working from the bottom up, you may want to adjust for that by reducing the Hat Height measurement by ½ – 1 inch depending on finished hat size. Less for baby sizes, more for adult sizes. When the desired hat height has been reached, begin doing decreasing rounds to form the crown of the hat.


Crown Decreases

To find out how many stitches to decrease, divide your number of cast on or beginning chain stitches by the lowest possible whole number that results in a single digit whole number. For example, let’s say my cast on number was 75. So I do a few calculations on my handy calculator and find that the lowest whole number that results in a single digit whole number is 15. (That is: 75 divided by 15 equals 5.) So I will decrease every 15th stitch on my first decreasing round. That means I’ll work 13 stitches, and then use the 14th and 15th stitches to create the decrease. I’ll repeat this all around and end up working a total of 5 decreases.


Note: If I worked decreases on every round the crown of the hat would become too flat, so every other round should be worked evenly with no decreases. This may change if you are using a tall stitch such as a double crochet, or if you are decreasing by anything less than 5 stitches per round. In cases such as those, you will probably want to work every third round evenly instead of every other round. The decreasing will then occur more quickly, resulting in a less elongated crown.


The next decreasing row will be a bit different. We have fewer stitches now, but we still want to have the same amount of decreases. So what we do is reduce the repeat. Instead of decreasing every 15th stitch, I’ll decrease every 14th stitch. That means I’ll work 12 stitches, and then use the 13th and 14th stitches to create the decrease. I repeat this all around and again end up working a total of 5 decreases. How beautiful is that? Ah what a little simple math can do!


Finishing Up

Continue in this pattern until you have less than 10 stitches left. Cut your yarn, leaving about 8 inches. Use this length to thread through the remaining stitches and cinch them tight to close up the hole at the top of the hat. Voila! Success!

If you have any questions or comments about sizing bottom up hats, please comment below!


  1. Pingback: Hat Sizing Chart - Make the perfect sized hat the first time! -

  2. Wanda Stanley

    Thanks for sharing, I have a difficult time when crocheting hats & getting the correct dimensions correct. Can’t wait to try later today.


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