Because safety shoe fitting involves so many variables, it is critical to have a basic understanding of shoe and foot sizes—or more accurately, the differences between these sizes.
Feet come in an unlimited variety of configurations. Shape, toe length, ball length and width (the only measurements we take at the present time) vary. Circumferential measurements all over the foot are continually changing as a person moves into different positions. The bones and muscles making up the foot can vary in length, thickness and function with each individual. So the components and movements create a never-ending combination.
Added to the personal traits of each foot are changes that occur with different activities as simple as sitting, standing, walking or running. It stands to reason that the foot is going to change with the different activities, terrains, and responsibilities we expect them to respond to. It is a known fact that feet fluctuate in size every day.
For all practical purposes, most people’s feet are longer at night than when they crawl out of bed in the morning. These are all changes that occur day in and day out. The foot, like the rest of the body, changes with weight gain and loss, and also significantly changes with age. As we get older, muscles relax and bony structures wear out and cannot function normally. As a consequence foot size is not a simple thing to understand, let alone to measure and capture.
In addition to weight change or age, your feet likely will change due to activity. In a work environment, you might have a job standing at a conveyor all day or you might have a job sitting at a desk or you might have a job climbing up and down a ladder. In all of these instances, the impact on your feet are very different.
When standing, you place up to 2 times your bodyweight in pressure on your foot. While walking that becomes 3 to 5 times your bodyweight. So for a 200lb man, that means he is putting up to 1,000 lbs of pressure on his feet every stride.
Now, imagine that same 200lb man carrying a big box of materials and you can see that downforce grow even higher. This downforce can cause your feet to splay or widen on impact. The shoes have to take this into account for proper fit.
The bottom line is that shoe fitting is equal parts art and science. While there is definitely science involved in the manufacture of the shoes, the need for a shoe fitting expert to translate the “last” of the shoe to the shape of your foot is priceless.
The “Last” Word
Shoes are made over a “last” or generic shape of the foot. Lasts are produced to the specifications of the manufacturer of the shoes.
Each different vendor (i.e. Justin, Wolverine, Reebok, etc.) designs their lasts to meet a certain shape of foot. They do this to have a competitive advantage over one another. In addition, how the manufacturer determines size is based on their last design. So one vendor may call their last a size 10 and another designate their last a size 11 – when they actually fit the same! In addition, a size 12 in one Hytest shoe may fit differently than a size 12 in another Hytest shoe. So even in the same vendor, the lasts will vary.
Much of this occurs because the manufacturers use different factories for their shoes. Justin Work for example, still makes many styles in the US. But they also have styles made in China. And the lasts in China are not exactly the same as the ones in the US plant. Therefore, there are differences in fit. Not picking on Justin, this is true of most brands.
In developing a last, there are a variety of measurements taken into consideration over and above the ones that we are able to measure (toe length, ball length and ball width). These include measurements like waist, ball, instep girth, throat opening, and the last ball break point. (I know, what was that last one!?) The list goes on, but the point is, each last has its own individual combination of measurements that the vendor hopes will proportionally fit a certain demographic of people.
Some vendors just shoot for the middle and try to fit as many people as possible. Since the last determines the shape and profile of the shoe, the first step is to match the shape of the foot and proper last proportionally as closely as possible while realizing that many other factors are going to affect the fit. For example, size is affected by style, patterns, and construction.
Also, of course, shoe manufacturers influence sizing. The last is “the last word” in the fit, conform, look and performance of the shoe you are fitting.
Brief History of Shoe Sizing
The history of shoe sizing, unfortunately, shows that many people were “doing their own thing”, and there was little standardization. The earliest recorded rationale for sizing goes back to England in 1374 when King Edward II decreed that three barley corns placed end to end would be the official measurement of an inch, for each barley corn (about 1/3 inch) would represent one full shoe size.
In 1856 a shoe sizing system was described in the Illustrated Handbook of the Foot, by Robert Gardiner of London. For the first time, there was some agreement of shoe sizing and, believe it or not, 1/3 inch was again used for a full size. Here in the U.S., that is still the measurement today: a difference of 1/3 inch for full sizes and 1/6 inch for half sizes.
In 1880, Edwin B Simpson of New York took the 1/3 inch system much further, developing a system that included proportional measurements (length, ball width, waist, instep and heel) for lasts and, therefore, for shoe sizes.
What proportional measurement really means is, each time a last/ shoe increases in length, there are proportional (predictable) increases in size/ measurement of the ball, waist, instep and heel. This is important because it gives you assurance that if the shoe doesn’t fit, when you get a shoe in another size (made on the same last) the second shoe will have the same characteristics but also be proportionately larger or smaller.
The difference in length of 1/3 inch applies to men’s and women’s shoes. A problem with the system involves the way it was developed. The sizing scales for each gender are different. Unfortunately, we do not start with a small number for length in children and go to the largest number for men.
One constant you will notice in men’s and women’s sizing is a 1 1/2 difference in sizes. That is, on the shoe size scale comparison, a man’s 8 will be the same length as a woman’s 9 1/2. But remember that this is only in toe length. When fitting, keep in mind the lasts are probably designed differently for the male or female foot.
Now, you may be saying “there were not safety toe work boots in the 1800’s and you would be right. These types of shoes didn’t come about until the expansion of the railroad in the US. In fact, it was the injuries during rail installation that led to the need for this type fo footwear and s standard to measure it. (Read about ASTM)
But even though the shoes you might be buying today have a safety toe in them, the rules that I am outlining here still apply. In fact, when someone says that a safety toe shoe and a regular shoe fit differently, they are not correct. If you fit a shoe correctly, the principles apply whether they have a safety toe cap in them or not.
It is important to understand that the measurement of a shoe’s width is not necessarily the measurement we take when we measure the foot with a Brannock device. What do we mean by that? The measurement of a last width, of the width marking the shoe, is the girth measurement at the ball of the foot. However, when we take a width measurement with a foot-measuring device, we are measuring the linear width of the foot at the ball.
As previously mentioned, the width measurement of the last, and thus the shoe, is a girth measurement, not a linear measurement. Thus when you are measuring the foot you are only getting a one-dimensional measurement. That is why foot evaluation is as important as the measurement. If your foot is very full and fleshy or has a very high instep, you must take this into consideration when selecting the shoe width. The width you measure with the measuring device, or the linear width of the foot, may not reflect the amount of volume of the foot or the width/ girth needed to properly fit the foot.
Also, when a last or a shoe width changes from a D to a E, the change may not translate to the shoe being wider across the bottom of the shoe or foot. In fact, the linear measurement may remain the same, but the shoe is wider because it is fuller or has more material across the upper.
The difference in each width is ¼ inch. For each change in width (D to E to 2E, Etc.), there is ¼ inch change in girth at the ball of the foot. As a shoe goes up in length, a ¼ inch increase in girth occurs automatically with each increase of a full size. Remember, each time a last/ shoe increases in length; there is a proportional (predictable) increase in size or measurement. Even though both are marked a B width, it stands to reason that you pick up more ball width with increased size, even though the width size remains the same.
Manufacturers and retailers limit the amount of their inventory investment by using less precise width markings. That is, instead of A, B, C, D widths, the shoes come in Narrow, Medium, Wide or XWide. This allows for some selection but does not require the store to have as much stock. Often, manufacturers who use N, M, or W width markings will identify these letters with traditional width letter sizing. The chart below explains how the different marking systems relate.
Here’s the deal. Just like there is no standard in lasts among manufacturers, the same is true with the marking of the sizes. For example, Cat may mark a shoe as a Wide and Keen may mark a shoe as Wide. The assumption is that they are the same width. However since the use of these “compromised” widths is up to the manufacturer, Cat’s Wide might be a 2E and Keen’s Wide might be a 3E or vice versa. This is why it’s best to have yourself professionally fit. You get an “interpreter” for all of those sizes.