How to Use a Brannock Device: A 2026 Step-by-Step Sizing Guide

Pressed for time? Here are the critical points for a perfect measurement:

• Measure Later in the Day: Feet naturally swell throughout the day. For the most accurate reading, measure in the afternoon or evening.
• Always Wear Socks: Measure while wearing the type of socks you'd typically pair with the shoes you intend to buy.
• Measure Both Feet: Most people have one foot that is slightly larger. Always buy shoes to fit your larger foot.
• Three Measurements Matter: The Brannock device provides three key data points: heel-to-toe length, arch length (heel-to-ball), and width. Your true shoe size is often determined by the longer of the first two measurements.
• Stand Up: You must be standing with your weight evenly distributed to get an accurate, weight-bearing measurement.

Invented by Charles F. Brannock in the 1920s, the Brannock Device is a specialized tool designed to measure the three essential dimensions of the human foot. It’s that metallic contraption you’ve seen in shoe stores your entire life, and it has remained largely unchanged for a century for one simple reason: it works flawlessly.

Unlike tracing your foot on paper, which only captures heel-to-toe length, the Brannock Device accounts for the relationship between your overall length and your arch length. The arch length (the distance from your heel to the ball of your foot) is often a better indicator of how a shoe will flex and fit than total length alone. Neglecting it is why a shoe that seems right can feel so wrong.

Before you begin, get familiar with the device's components. Knowing what each part does is key to an accurate reading.

• Heel Cup: The curved area at the back where you'll firmly place your heel.
• Heel-to-Toe Length Scale: The main set of numbers running down the center that indicates standard shoe size based on total foot length.
• Arch Length Pointer: A slider on the side that you'll move to align with the ball joint of your big toe. This measures your arch length.
• Width Bar: The slider at the front of the device that you'll move to touch the side of your foot, measuring its width.
• Width Chart: The curved lines on the width bar that correspond to width sizes (e.g., A, B, C, D, E).

We'll start with the right foot. Follow these steps carefully, and don't rush the process.

Step 1: Prepare the Device

Make sure all the sliders-the arch length pointer and the width bar-are moved to their outermost positions to create a clear space for your foot.

Step 2: Position Your Foot

While seated, place your right foot into the device, ensuring your heel is pushed back snugly into the heel cup. The fit should be firm but not forced. Once your foot is in place, stand up with your weight evenly distributed on both feet. This is crucial, as your foot lengthens and widens under your body's weight.

Step 3: Measure Heel-to-Toe Length

Look straight down at the tip of your longest toe (which may not be your big toe). The number it points to on the central scale is your heel-to-toe length. Make a mental note of this size.

Step 4: Measure Arch Length (Heel-to-Ball)

Without moving your foot, slide the arch length pointer forward so the inner curved edge cups the ball joint of your big toe. This is the prominent joint on the inside of your foot where it flexes. The number the pointer's arrow indicates on the scale is your arch length.

Step 5: Compare and Determine Your True Length

Now, compare the two numbers from Step 3 and Step 4. Your correct shoe size is the larger of these two measurements. For example, if your heel-to-toe length is an 8 but your arch length is an 8.5, your true shoe size is 8.5. This is the most common point of confusion and the device's most powerful feature.

Step 6: Measure Foot Width

Using the size you determined in Step 5, locate that number on the movable width bar. Slide the width bar inward until it just touches the side of your foot. The line on the device that aligns with the corresponding shoe size on the width bar indicates your foot width (e.g., B for narrow, D for standard, EE for wide).

Foot asymmetry is incredibly common. For many people, one foot is slightly longer or wider than the other. Failing to measure both feet can lead to discomfort, blisters, and other foot-related issues.

Follow the exact same six steps outlined above for your left foot. Once you have the final size and width for both feet, use the measurements of the larger foot when buying shoes. You can always add a small insole to the shoe for the smaller foot, but you can never make a tight shoe bigger.

Let’s review with a clear example. Imagine these are your measurements for your right foot:

• Heel-to-Toe Length: 10
• Arch Length: 10.5
• Width: The pointer lands on the 'D' line when aligned with the 10.5 size.

In this scenario, your correct shoe size is 10.5 D. You ignore the smaller heel-to-toe measurement and use the longer arch measurement as your true size. This ensures the shoe's arch and flex point align correctly with your foot's anatomy.

Getting a perfect measurement requires avoiding these simple errors:

• Measuring While Seated: Your foot changes shape under your body's weight. You must be standing for an accurate reading.
• Forgetting Socks: This adds a small but significant amount of volume. Always measure with the appropriate socks.
• Measuring in the Morning: Your feet are at their smallest when you wake up. Measure in the late afternoon for a true-to-life size.
• Only Using Heel-to-Toe Length: The biggest mistake is ignoring the arch length. Remember to take the larger of the two length measurements.
• Not Firmly Seating the Heel: If your heel isn't all the way back in the cup, all your measurements will be off.

Children's feet grow quickly and need accurate sizing to support healthy development. The Junior Brannock Device works on the same principles as the adult version but is scaled for smaller feet. The process is identical: measure heel-to-toe length, arch length, and width, and take the larger of the two lengths as the true size.

Given how fast kids' feet grow, it's a good practice to measure them every three to four months. Investing in a junior device for home use can save you from buying ill-fitting shoes and help you monitor their growth properly.

Your Brannock size is the most accurate starting point you can have, but it's not a universal law. Shoe sizing can vary between brands and even between different styles from the same brand. An athletic sneaker will fit differently than a leather boot or a high heel.

Use your Brannock measurement as your baseline. From here, you can make more educated decisions:

• Sneakers: Often run true to your Brannock size. Check our Sneaker Drop List for notes on specific models that might run large or small.
• Boots: You might size up a half-size to accommodate thicker socks, especially for winter wear.
• Heels: The shape of the toe box dramatically affects fit. For pointed-toe heels, you may need to go up a half-size. Our Heel Height Guide can help you find comfortable options.
• International Brands: Sizing from European or UK brands is different. Use your precise measurement with our Shoe Size Converter (Intl) tool to find your equivalent size without guesswork.