Z-CoiL Footwear generally runs true to size.  Order the size that you most normally wear.  If your current shoes are a variety of sizes, use the chart below to figure out what size you are in a Z-CoiL.  If you wear a half size, please order the next size up unless it is one of the ones that runs in an E width (see “width” below), and follow the directions for fitting a 1/2 size shoe below.

You can use the chart below by either measuring your foot in inches or centimeters or using European sizing.  Measure your foot by having someone outline your foot on a piece of paper and measure from the longest toe to the back of the heel to get the size in inches or centimeters.


Sizing Chart


All of our Z-CoiL footwear are built in a E width.

All our shoes are built with a rounded heel and raised arch for  a great ergonomic fit.  We strive to support each contour on your feet.   The toe box on a pair of Z-CoiLs is wider than normal shoes and designed to prevent irritation in the toes and ball of the foot.    Its important that you wear shoes that prevent cramping or squeezing of the toes.  Tension on the toes can easily lead to bunions and disfigurement of the toes and ball of the feet.  Its important to set your toes free and allow them to spread out naturally with each step.

1/2 Sizes

Z-CoiL does not make half sizes.  Instead all Z-CoiL Footwear ship with an extra 3 mm insert that makes up 1/2 size. If you are between sizes, add the insert as follows:

1.  Remove the Z-CoiL Insole from the inside of the shoe.

Insole horizontal view

2.  Insert the 1/2 Size Insert

One Half Size Insert from Z-CoiL

3.  Replace the Insole

The video explains how to make the simple adjustment.

3mm insertClick Here:

Spring Strength:


Z-CoiL has 4 different sized springs.  The size of the shoe dictates what size of spring is loaded at the factory.  In some cases, customers will choose a softer or stiffer spring based on their weight or gait type.  Your objective should be to compress the spring about 75% during a normal walk (or a normal run — if you run in Z-CoiL’s).  If you “bottom out” on the spring, you may want to consider a stronger spring.  If you feel your shoe is too stiff, you may consider a softer coil.   The vast majority of consumers do not change the factory spring strength.

  • Women’s sizes 5~7 are factory loaded with a small spring.
  • Women’s sizes 8~11 & M8~9 are factory loaded with a medium spring.
  • Men’s 10~13 are factory loaded with a large spring.
  • Men’s 14+ are loaded with an XL spring.
Coil Size Typical weight Weight range of
successfully fitted customers
6.2 mm Small up to 150 lbs. 90 to 300 lbs.
6.5 mm Medium 120 – 200 lbs. 90 to 350 lbs.
7.2 mm Large  160 – 240 lbs. 90 to 350 lbs.+
7.5 mm X-Large 220 lbs. + 90 to 350 lbs. +