The Boot Shaft Explained: What It Is and How to Measure It

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by  Bradon Matthews | Last Updated: 

There’s nothing more disappointing than buying a pair of boots in the right size, only to find out they just don’t fit comfortably on your calves or ankles.

The problem is that standard shoe sizes don’t account for the boot shaft. 

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This is especially frustrating when looking for work boots or any boot that serves a protective function. 

Luckily you can learn to measure the shaft of your boot, ensuring you get the proper fit and protection you need.

So, what is the boot shaft? And how do you measure it?

How to Measure the Boot Shaft

While not excessively complicated, measuring the boot shaft does require a bit of know-how. 

To start, you’ll need a tape measure and your boot. Place the boot on the floor in an upright position. 

Make sure the collar (the uppermost part of the boot where the opening is) is fully elongated. If the boots have been worn in, you may need to pull it taught to ensure you get an accurate measurement.

Anatomy of a Western Boot Diagram

When measuring the shaft, you want to start at the top of the arch. This is the point where the sole attaches to the boot.

How to Measure the Boot Shaft Diagram

The distance from the top of the arch to the collar is your shaft height. 

In addition to the shaft height, you may also want to know the shaft circumference. To measure the shaft circumference, you’ll need a flexible tape measure. 

Simply wrap the tape measure around the shaft of the boot and note where it meets to get your circumference measurement.

You may want to do this at multiple points on the boot, as the calf circumference and ankle circumference often differ.

Boot Shaft Height Chart 

You can use the height of the boot shaft to split boots into a few categories.

Type of BootCoverageHeight
Over the knee bootsAbove the knees18″+
Tall bootsJust below the knees13 ¾’’ to 17 ¾’’
Mid-calf bootsHalfway between ankle and knee9’’ to 13 ½’’
Ankle bootsOnly cover ankle3’’ to 8 ¾’’

A shaft height of 3 to 8 ¾ inches is typically classified as an ankle boot. As the name implies, ankle boots cover only the ankle. Most dress boots will fall in this range.

Mid-calf boots fall between 9 and 13 ½ inches at the shaft. Most work boots will fall in this range, as they strive to balance flexibility and protection. 

Boots with a shaft height of 13 ¾ to 17 ¾ inches are considered tall boots. These boots typically stop just short of the knee. While these boots offer a great deal of protection, they also tend to be very heavy because of the amount of material. 

Anything past 18 inches in height is an over the knee boot. These are relatively rare and typically created for specific tasks and occupations. 

How Do You Stretch the Boot Shaft?

Should you find your calves or ankles constricted by your boots, you’ll probably wonder if there is a way to stretch your boot shafts to better accommodate your lower legs. Luckily, this can be done.

The first way to stretch your boots is to simply continue wearing them. As time goes on, your boots will naturally stretch around your ankle and calf.

Ariat workhog boot in workshop


While this method is the cheapest, it’s also the most uncomfortable. It may take quite a while for your shafts to stretch, and the interim can be a bothersome experience.

If you want to speed up the process, you have a few options. 

Option #1: Use a Boot Stretcher

You can purchase a boot stretcher to stretch out the calf and ankle portions of your boot shafts. Our pick is the FootFitter because of its durability and versatility. Crafted from tough aluminum, the FootFitter is strong enough to stretch even the stiffest boots. 

In addition to the shaft, this boot stretcher also has the ability to stretch the instep. You’ll be able to use the FootFitter to adjust the fit of any boots you purchase in the future. This is truly a product you’ll be glad you have on hand. 

What is a Boot Stretcher?

A boot stretcher is an adjustable device that you place in the shaft of your boots. 

FootFitter Cast Aluminum Combination Boot Instep and Shaft Stretcher
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You can adjust the boot stretcher to the same circumference as your legs. By doing so, you will force the leather to expand without having to go through the painful process of wearing your constricting boots till they break in.

Option #2: Try Leather Stretching Spray

This method is significantly cheaper than purchasing a boot stretcher. 

To use leather stretching spray like this highly regarded one from FootFitter, simply spray your boots and put them on. They will be tight initially, but after an hour or two the leather should start to conform to your legs properly. This method is essentially an expedited break-in period. 

Leather stretching spray works by making the leather more supple. When applying the spray, make sure you coat each part of the shaft. This will ensure that the leather molds to both your calf and ankle properly and minimize any discomfort you may experience.

FootFitter Shoe and Boot Stretch Spray
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Option #3: Take Them to a Cobbler

Smiling Cobbler

The cobbler will most likely use both leather stretching spray and a boot stretcher to achieve the same effect, albeit with far less effort on your part. 

One of the benefits of going to a cobbler for boot stretching is that you won’t risk damaging your boots. Using a boot stretcher or leather stretching spray at home is fairly safe, but there’s a chance you’ll wind up damaging your boots. The cobbler avoids this issue.

That said, a cobbler is going to be the most expensive option when it comes to stretching out your boot shafts. 

Average Boot Shaft Circumference

The circumference of boot shafts varies depending on a variety of factors. The height of the boot influences the circumference, as calf height boots will naturally require larger openings than will ankle boots.

That being, the most common circumference is about 14 inches. This is a safe place to start when looking at the circumference of boots online. 

If the manufacturer or retailer doesn’t state otherwise, it’s fairly likely that the circumference is around 14 inches. 

Ariat Boots Review Workhog and Midtown Rambler

If you want to ensure the best fit, you’re better off taking your own measurements though. Knowing your ankle and calf circumference will allow you to select a pair of boots that fits perfectly in the shaft.

As a general rule of thumb, you want to have about half an inch of room between your boot shaft and your calf or ankle. So, if your ankle is 13 inches, you’d want a boot with a shaft circumference around 13 ½ inches. 

This is just a starting point though. Trying on different pairs of boots will allow you to find what fits your foot best.

What’s the Purpose of the Boot Shaft?

One of the biggest functions of the boot shaft is to add stability to the ankle. Having a boot that wraps the ankle adds support to the joint, making it less likely that you might sprain or otherwise injure your ankle.

This is particularly true of ankle boots. These boots don’t offer large swaths of material to protect the lower leg, but the bit of shaft they do have cradles the ankle while still allowing for plenty of mobility.

That said, with taller boots, the main function of the shaft is to protect the leg. Work boots and western boots exemplify this perfectly. The taller shafts wrap the calf to offer a layer of insulation and cushioning against anything that might come into contact with your leg. 

This is part of the reason many work boots feature layers of thicker material. Construction workers or those in similar professions are often faced with situations in which heavy objects could slam into their lower legs or feet. 

By extending up the shin and calf, the boot shaft guards against potential injury.

Thursday Boots Logger side profile while walking

Additionally, higher boot shafts help keep deprise from entering the boot. Having the opening higher up the leg means dust and small objects are less likely to get kicked up into the boot’s interior.

How Does It Affect Fit? 

The shaft of the boot can have a significant impact on the way the boot fits overall.  

A boot with a snug shaft will help keep the foot in place. This is especially true of boots with laces, as the lacing can be tightened up the shin. This will keep the boots snug on the foot, even if they are slightly roomy.

By contrast, overly tight shafts can mean that your normal shoe size will be too small. If the shafts are too tight, you won’t be able to get the boot onto your foot as you normally would. 

Properly fitting shafts will add a snugness and security to the fit of your boots without constricting your ankle or calf.

How Does It Affect Comfort?

When the shaft of your boot is too big, it can cause your foot to move around inside. This can lead to blisters and heel slippage, both of which are annoying and can ruin your experience with your boots. 

Having the shaft circumference too tight around the ankle or calf can also make your boots highly uncomfortable. This can lead to a constricted feeling, limit your ability to move, and in extreme cases, cut off circulation to the foot.

If there’s a particular pair of boots you really want, take the time to check their shaft measurements. If they’re too small, you’ll want to plan to stretch them once purchased.

Conclusion

The boot shaft is the tall part of the boot that differentiates it from a typical shoe. They offer support and protection for your ankle and calf.

When measuring the height of your shafts, start at the arch, not at the sole. The circumference should be about half an inch wider than your leg. This can be adjusted using leather stretching spray or a boot stretcher.

Do you know the measurements of your boot shafts? Subscribe to our YouTube channel for more guidance on all things boots. 

FAQs

What does shaft circumference mean in boots?

The shaft circumference of a boot is the circumference of the cylindrical part of the boot that extends up the ankle and calf. To get this measurement, simply wrap a flexible tape measure around the boot shaft and record where it meets itself.

Where is the shaft of a boot measured from?

When measuring the height of a boot shaft, start at the top of the arch. This is the point where the sole and the bottom of the boot itself meet. Don’t start from the sole itself, as this isn’t considered part of the shaft.

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