Do Chacos Run Big Or Small? Compared to Nike & Birkenstock

The adjustable straps of Chacos allow you to fit with your feet. However, it might be challenging to find your exact Chaco size, especially when Chacos only come in whole sizes.

So, do Chacos run big or small, or true to size? Is choosing Chaco sizing simply by going down or up a whole size?

This detailed guideline will help you to find the perfect size for your first Chacos.

Do Chacos Run Big Or Small According To Users?

Chacos are designed to fit various foot shapes and sizes. However, their sizes are more complicated than other footwear brands. Instead of the overall foot length, Chacos’ sizes are measured by the distance from heel to ball.

Depending on the foot shapes and Chaco size charts, Chaco sandals can be divided into 3 width groups – Wide, Regular, and Medium.

Chacos Size Chart

Size marks and their meanings

Besides sizings, you should know some important size marks and their meanings to pick up the Chacos that fit you most. There are two typical size marks on the heel of all Chacos – the fit type and the gender.

  • Fit type

On every Chaco shoe, there is a size mark to help you detect its fit type. A regular-width shoe is expressed with a dot, while a wide-width one is expressed with a dash.

  • Gender

Chacos are not unisex. Their gender types are written next to the size number. The “W” stands for Women’s, while the “M” stands for Men’s.

Women’s Chacos size charts

USA – Women UK EUR JPN (cm)
5 3 36 22
5.5 3.5 36.5 22.5
6 4 37 23
6.5 4.5 37.5 23.5
7 5 38 24
7.5 5.5 38.5 24.5
8 6 39 25
8.5 6.5 39.5 25.5
9 7 40 26
9.5 7.5 40.5 26.5
10 8 41 27
10.5 8.5 41.5 27.5
11 9 42 28
12 10 43 29

Men’s Chacos size chart

USA – Men UK EUR JPN (cm)
7 6 40 25
7.5 6.5 40.5 25.5
8 7 41 26
8.5 7.5 41.5 26.5
9 8 42 27
9.5 8.5 42.5 27.5
10 9 43 28
10.5 9.5 43.5 28.5
11 10 44 29
11.5 10.5 44.5 29.5
12 11 45 30
12.5 11.5 45.5 30.5
13 12 46 31
14 13 47 32
15 14 48 33

Toddlers & Kids’ Chacos size chart

USA – Kids UK EUR JPN (cm)
10 9 28 16
10.5 9.5 28.5 16.5
11 10 29 17
11.5 10.5 29.5 17.5
12 11 30 18
12.5 11.5 30.5 18.5
13 12 31 19
13.5 12.5 31.5 19.5
1 13 32 20
1.5 13.5 32.5 20.5
2 1 33 21
2.5 1.5 33.5 21.5
3 2 34 22
3.5 2.5 34.5 22.5
4 3 35 23
4.5 3.5 35.5 23.5
5 4 36 24
5.5 4.5 36.5 24.5
6 5 37 25

Check more: Do Yeezy Run Big Or Small? Yeezy Sizing Chart For Women & Men

Chacos Fit Vs Other Footwear Brands

Chaco sizing compared to Nike

It is hard to convert your shoe sizing from Chaco to Nike since these two brands have different methods of sizing measurement.

Chacos have an orthopedic footbed that needs a special measurement than other sneaker brands. For this reason, Chacos sizing is measured as the length from heel to toe, but it is only available in whole sizes. Besides, Chacos also have 3 width options for regular and wide feet.

The size of Nikes, however, is measured as the overall foot length and is available in whole sizes and half sizes. Almost all Nikes are true to size for slim feet. If your feet are wider, you should go a half size bigger than your current size.

Chaco sizing compared to Birkenstock

While Chacos fit various foot shapes and sizes, Birkenstocks run true to size. Still, these two sandal brands have adjustable straps to let you customize your sizing to get the best fit.

Another difference in sizing between these two brands is that while Chaco offers only whole sizes, Birkenstock offers whole sizes and half sizes.

Chaco has larger size ranges from 5 (US Women), 7 (US Men), and 3 (US Kid), whereas Birkenstock has smaller size ranges from 2-2.5 (US Women, 5-5.5 (US Men), and 6-6.5 (US Kid).

Last but not least, Chaco offers 3 width options, including Medium, Wide, and Regular. Conversely, Birkenstock has only 2 options – Regular and Narrow.

Customize Your Chacos Sizing With Straps

Although Chacos only come in whole sizes, you can customize your shoes by loosening or tightening two adjustable straps. These straps make the shoes wrap your feet better and maintain your natural walking gait. Wearing Chacos with straps also avoids your shoes from slipping off your feet.

Chaco shoes come in two basic styles – the Z/1 and Z/2.

The Z/1 style is easier to customize, while the Z/2 style is harder for new Chaco owners. Since the straps are too thin and long, and they wrap around your feet in a complicated way, you should have experience in using Chacos to have it done rightly.

Adjust Z/1 straps

Here is the detailed procedure for handling Chaco Z1 classic sizing customization.

  1. Loosen the straps by opening the buckle.
  2. Pull the second webbing near the pinky.
  3. Create an opening by pulling the webbing that wraps over the pinky toe.
  4. Put your foot into the shoes, then tighten the webbing from the big toe to the instep to get a secure fit.
  5. Pull the webbing/strap to the buckle to fully cover your foot’s upper.

Adjust Z/2 straps

Z/2 straps

The Z/2 style features a toe loop, so the procedure can be a little bit different.

  1. Loosen the straps to open the buckle.
  2. Gently pull the webbing over the pinky toe, the big toe, and the pinky toe to create a big opening.
  3. Put your feet into the shoes and begin tightening the 3 straps on the knuckle, toe, and buckle.
  4. Tighten the strap over the knuckle bone. This will also tighten the webbing over the instep.
  5. Tighten the webbing over the big toe. Remember not to over-tighten this webbing with the webbing at the bottom.
  6. Finally, tighten the buckle strap to make a secure fit.

How To Find The Right Size For Your Chacos?

Below is some simple clues to assist you in finding the appropriate size for your Chacos. Since Chacos doesn’t have half sizes, you should choose the larger full size (or run one size bigger) if you fall in between two sizes.

1. Use a Brannock Device

Brannock Device

A Brannock Device is an old-schooled yet useful, simple device to get your exact shoe sizes at home. This device has been widely used for decades to measure footwear products of Chaco, Nike, Adidas, etc. It is simple to use and affordable.

Measuring foot width is not a simple task and is impossible to guess without a standard measuring device.

Some people thought that their feet are wide, but actually, they are regular width. In other cases, some people thought that they have small feet, but their toes are wide.

So if you are about your Chacos sizing, get a Brannock device. You can detect your actual foot size in two ways:

Calculate your arch length and your heel-to-toe length

You can measure the length from heel to your big toe (or your heel-to-toe length) and the distance from heel to the widest part of your feet, or foot’s ball (or your arch length). There are two cases:

  • If the arch length is smaller than the heel-to-toe length, you should choose regular-fit Chacos.
  • If the arch length is bigger than the heel-to-toe length, you should choose medium or wide-fit Chacos. Choose the Chacos size that is nearest to your arch length.

For example, if your heel-to-toe length is 9 inches and your arch length is 8.5 inches, you should choose wide-fit Chacos with a size of 9 inches.

Calculate your foot width

This number is measured from your heel to the widest part of your foot.

  • Width is “B” = medium-fit Chacos
  • Width is “C” or “D” = regular-fit Chacos
  • Width is “E” or “2E” = wide-fit Chacos

2. Fit your Toe

Another clue to know whether your Chaco sandals fit you or not is to check the toes’ position.

If the sandals are too long, your feet will feel bulky, while your arch and your heel will hurt. Conversely, if the sandals are too short, your toes will go off the edge.

The perfect Chacos should securely hug your feet but not add extra weight to your feet.

3. Luvseat Orthopedic Footbed

Luvseat Orthopedic Footbed

Chacos come with Luvseat Orthopedic Footbed, a feature certified by the American Podiatric Medical Association (APMA) to maintain good stability and promote good health for your feet.

Since a foot has 26 bones and 33 joints to be protected, you should ensure that your heel and your arch are firmly hugged while on the move.

If the sandals are too wide, your feet arch and slide around the shoes. Thus, your stability might be badly decreased.

When wearing narrow Chacos, the footbed can contact the arch and affect your walking gait. Nonetheless, the heel strap can hurt your feet and cause blisters.

4. Subtalar Joint

The highest point of the arch in the Chacos’ footbed should support the subtalar joint. You can check this sizing fit by drawing a straight line throughout the foot from the front of your ankle.

5. Heel Cup

Our heels have a pad of fat acting as a natural cushion, and the Luvseat Footbed cups our heel for maximum cushioning and all-day comfort. Thus, you should ensure that you have selected the proper shoe width.

If the shoes are too wide and the heels aren’t cupped, the cushioning effect can be diminished and the overall stability can be lessened.

And vice versa, if the shoes are too narrow, the heel can be uncomfortable, the arch doesn’t stay in one place, and the straps can be too tight.


1. Should you size up or down in Chacos?

If you are between sizes, you should go 1 size up. Chaco sandals have adjustable straps, allowing you to tighten or loosen the straps to get a secure, comfortable fit.

You can also contact the Chaco service team to get your straps shortened or lengthened.

2. Are men’s Chaco wider than women’s?

Chaco sizing measurements for men and women are the same. However, due to some differences in foot shapes and body posture, some Chaco shoe models for women have X-shaped straps instead of wide webbing.

These two narrow straps make the shoes look more feminine and offer greater support to women’s feet.

3. Do Chacos have half sizes?

Chacos only come in whole sizes. If your feet are between sizes, you should go 0.5 sizes down and check if your arch fits the shoe’s arch or not.

4. Should you tighten your Chacos?

Yes, you should tighten your Chacos with straps to make them fit your feet’ shape and width.

5. Do Chacos have the size printed on the sandals?

Chaco sandals do have printed sizes on them. Yet, their size marks are slightly different than other footwear brands. For example, the “W” on the back of the shoe means “Women’s”, not “Wide”. Similarly, the “M” means “Men’s”, not “Medium”.


In sum, Chaco sandals are designed to fit from the smallest to the largest feet. So, Chacos run big, small, or true to size depending on your foot width, fit type, and gender.

This fitting is unlike your other shoe brands, so you should use a supporting device (like Brannock), or have a short walk in-store to check your shoes.

And remember that loose is always better than tight. You can use the straps to customize your Chacos sizing.

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