Sonder Bikes
Foot length is just the start. Width, volume and arch type all affect boot fit. Here's how to measure all four at home.
Getting your boot size right before buying online takes ten minutes and can save you the hassle of a return. Feet are more complex than a single length measurement: width, volume, and arch profile all affect how a boot fits. This guide covers all of them.
What You Need
- A piece of paper larger than your foot
- A pen or pencil
- A ruler or tape measure in millimetres
- A wall
Step 1: Measure Foot Length
Place the paper on a hard floor with one edge against the wall. Stand on it with your heel touching the wall and your weight evenly distributed. Mark the end of your longest toe with the pen held vertically.
Measure from the wall edge to the mark in millimetres. Repeat on the other foot; most people have a slight difference in length. Always fit to the larger foot.
Measure in the afternoon. Feet expand through the day and can vary by half a size or more between morning and evening. An afternoon measurement gives the most accurate reading for a boot that will be worn on active days.
Step 2: Measure Foot Width
Stand on the paper and mark the widest point of your foot on both sides. This is usually across the ball of the foot, at the base of the toes. Measure the distance between the two marks in millimetres.
Width varies significantly between people and is one of the most common reasons a boot that is the correct length still feels wrong. If your feet are consistently wider than average for your length, look for wide-fit options or boots with a roomier forefoot last.
Step 3: Identify Your Arch Type
Your arch type affects which insole suits you and can affect boot selection. The wet foot test is the simplest method.
Wet the sole of your foot, then step onto a surface that shows a clear print. A paving stone, a piece of dark card, or a dry floor all work.
- Full flat print with no visible arch: low arch (flat foot). You may benefit from a supportive insole
- Print with a moderate band connecting heel to forefoot: normal or neutral arch. Standard insoles suit most people in this category
- Print showing only heel and forefoot with no connecting band, or a very narrow one: high arch. High-arch insoles or custom orthotics may be worth considering
See: Insoles for Walking Boots: Customising Your Fit
Step 4: Assess Your Volume
Volume is the three-dimensional space your foot occupies inside the boot, meaning the height and depth, not just the length and width. High-volume feet fill a boot firmly; low-volume feet move around inside the same shell.
Signs of high volume: shoes consistently feel tight across the top of the foot, laces are always under tension at the instep, or the tongue gets pushed to one side.
Signs of low volume: feet feel loose or move around in shoes, heels are difficult to keep in place, shoes feel sloppy even when the length is correct.
Volume can be adjusted with insoles: a thicker insole fills space and lifts the foot, helping a low-volume foot feel more secure. For a high-volume foot, a thinner insole or a boot with a higher last is the answer.
Understanding Boot Sizing
Walking boots are sized in EU measurements. UK sizes are provided as a guide, but EU sizing is more precise.
| UK Size | EU Size | Foot Length (mm) |
|---|---|---|
| 4 | 37 | 230–235 |
| 5 | 38 | 235–240 |
| 6 | 39–40 | 240–250 |
| 7 | 41 | 255–260 |
| 8 | 42 | 265–270 |
| 9 | 43 | 270–275 |
| 10 | 44 | 275–280 |
| 11 | 45–46 | 280–290 |
Should you size up? The standard advice to go half a size up exists for a reason: feet swell on long walks, and you need enough toe room on descents to avoid bruised toenails. If your measurement puts you exactly on a size boundary, go up rather than down. A boot that's slightly long can be managed; a boot that's too short cannot.
If You're Between Sizes
Go up. A boot that's slightly too large can be adjusted with a thicker sock or a volume-adding insole. A boot that's too small causes toe bruising on descents and cannot be corrected.
Still Not Sure?
Visit an Alpkit store. Our fitting staff will measure both your feet, assess your arch type and volume, and help you find the right boot and insole combination. It's the most reliable way to get fit right.
Alternatively, contact us before ordering and we'll talk you through it.