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How to select the correct shoe size for Bikepacking, Backpacking and Hiking

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Measure your feet

Take the measurement from the most prominent toe point to the most prominent heel point. Your feet usually swell during the day, so take the measurement in the evening. If you are going to wear particularly thick socks, measure with these on.

Most of us have one foot larger than the other. It would be quite unusual to be able to buy two different size shoes as a pair, if this is possible it would be ideal, alas, normally it is not possible, so buy for your largest foot.

My right foot measures 248mm, going by the chart at the bottom of the page, this roughly equates to a UK size 7. My left foot measures 252mm and that equates to roughly a UK size 7.5

If I was buying a casual shoe I would simply go for a UK Size 8. If I was buying footwear for a vigorous activity I would need to add 15mm (20mm if being used in an extremely hot climate) to the largest measured length. 252mm + 15mm = 267mm, this is the length I need to look up on the chart.

Size 9 are for 271mm length feet, this gives me the 15mm additional ‘rule of thumb’ length and is proven out by the fact that the UK size 9/US size 11 Altra Lone Peaks I wear have given my feet a very comfortable time over the past 18 months. I noticed in my recent bikepacking tour that riding on a very hot day, 35+ Degrees C, by the time my feet swell, the shoes are tighter, so perhaps next time I may go up a half size.


Shoe width

Generally the width of the shoe increases as the size gets larger. Not only does the width gets wider, the depth of the shoe also increases. The measurement for width is taken across the widest part of your foot, the bunion point. As with shoe size charts, the width assignment of whether it is Regular, Narrow or Wide varies from country to country, manufacturer to manufacturer.

My right foot measures 250mm long and 90mm wide, this sets me within the Regular zone. By my calculations, the width of the foot in a regular shoe is approximately 37.5% to 38% of the length

Measure yours to see what range you are in. If you need a narrow or wide shoe, the range of footwear available will be considerably reduced but it is essential you buy what will suit your feet


Wide toe box

You may have noticed that the shape of modern footwear nowhere near resembles the shape of your foot. Our toes are squeezed into tapered pointy shoes, even if the arc from the big-toe area to the small toe area may be slightly rounded, if we could see how our toes sit, it would be found that the toes and forward foot bones are unnaturally positioned and squished up

This squeezing up can cause bunions, hammer toes, Morten's Neuroma, in-growing toenails, numbness and numerous other foot ailments

I only have experience with one type of wide toe box shoe, and that is the Altra Lone Peak, so have no comparisons to offer you but I can say that the wide toe box on the Altra has transformed my feet, no longer are they painful due to in-growing toe nails, numbness and Morten's Neuroma

**Update** I now have experience of Topo Ultraventure Pro wide toe box trail runners. See my comparison video between these and the Altras here

For your current or future foot-health, I would say seek out your chosen footwear in a wide toe box version if at all possible

It is important to note that wide shoes are not the same as wide toe box shoes

Different width shoes are a different fit for the whole foot, being tailored to slim, regular or wide feet. The wide toe-box is just the shape around the toes

Foot arch type and insoles

If you don't already know what type of arch you have, it's worth finding out. This will give you an idea as to whether you need to replace your chosen shoe insert for a more appropriate one. You may even be able to select your chosen shoe with the correct insert and also correct sole for your foot

To see what type of arch you have, do the following:

  1. Place a piece of cardboard on hard ground such as tiles, approx. 2 metres long

  2. Place your feet in a bowl of water

  3. Shake off the excess water

  4. Walk along the cardboard

  5. Observe the wet print your feet have left

  6. Shown below, these are options of the imprint you will observe

  7. If possible find a shoe suitable for your arch type or seek out a suitable insole

You may already have a favourite orthotic insole, if you feel the insole is particularly thicker than the insole supplied with shoes, you should consider if you need to add another millimeter or two to your foot length, as the width and depth of the shoe will increase slightly to account for this

If you don't already have the correct insole, purchase those first and see how they change the fit of your existing shoes

There may also be another reason you need a special insole, in my case that is to raise my heel because the only wide toe box shoes I have are zero drop (where your foot is flat on the floor). Zero drop does not work well for my Achilles tendon, so I raise my heel around 8mm

Foot prints, high arch, flat foot and normal
Foot arch types diagram



Don’t get hung up on the 'size' you have always bought. Measure your feet, then add the additional 15mm-20mm. Find the appropriate footwear you want to buy, then seek out the correct Size Reference chart for those specific shoes. Select the correct size for your foot length and also for your foot width, taking into account any special insole you may need. If you can, select a shoe with a wide toe box

Not all charts list the foot length or width, this can make things tricky. If you are buying online and cannot establish your size from a foot length, select a supplier that has a hassle-free returns policy


Recap and additional information

  1. Shoe sizes across the globe are not consistent, they depend on:

    1. The country of manufacturer or sale

    2. The manufacturer itself

    3. The gender the footwear is intended for

    4. Military use

    5. Your age (split into Baby, Child, Adult groups for ladies and men)

  2. Consider any peculiarities in your feet or any injuries you are nursing

  3. Have your feet measured at a shoe store if it is possible, both length and width. If this is not possible measure your feet, in millimeters

    1. Stand barefoot, with the weight evenly distributed between both feet

    2. Measure both feet, from your most prominent toe to the most prominent part of your heel

    3. Add an additional 15mm for normal activity or 20mm for activity in extreme heat, to your foot measurement

  4. Once you’ve found the type and style of shoe you want, try to find that manufacturers size chart online

  5. Buy for your largest foot, unless you are lucky and can buy different sizes for each foot

  6. When it comes to measured length, note that the internal size of the shoe and external size of the shoe will obviously differ (so don’t measure the outside of your existing shoes!)

  7. Seek out whether any quoted measured lengths are saying:

    1. Is it the internal cavity size for the size quoted

    2. Does it include 'moving room' for the size quoted

  8. A rule of thumb would be you need your internal shoe size cavity to be at least 15mm longer than your actual foot size, more if you are hiking, biking or running in an extremely hot climate

  9. The Euro Shoe sizes don’t seem to increment in a linear fashion, sometimes they increment by 5mm each full size up in UK/US/AUS Sizes, then sometimes they jump 10mm between one UK/US/AUS size

For example, Euro Size 40 = 255mm, the next size up Euro Size 41 = 260mm (5mm change)

But Euro Size 42 = 265mm, the next size up Euro Size 43 = 275mm (10mm change)

The Euro Sizes appear to inconsistently equate to UK, USA and Australian Sizes

Exercise Caution when using Size Charts (this one included)

There are many size conversions guides available online, these do not give consistent results, therefore the size charts you reference should be taken as a rough guide.

Only the manufacturers guide for the shoe you are buying can give you the correct size to order. To be able to gauge your correct size, the guide will need to show a foot measurement.

The size chart below is to be used as a rough guide only, as already noted, the best course of action in buying the correct size footwear is to measure your feet and seek out the specific manufacturers sizing guide. Reference any generic size guide charts as a sanity check only!


Useful conversion information


  • Australian Ladie’s Sizes are the same as USA Ladie’s Sizes

    • For example, Australian Ladie’s size 8 = USA Ladie’s size 8

  • Australian Ladie’s Sizes are equal to two sizes up from UK Ladie’s Sizes

    • For example, Australian Ladie’s size 8 = UK Ladie’s size 6

  • UK Ladie’s Sizes are equal to two sizes down from USA Sizes

    • For example, UK Ladie’s size 8 = USA Ladie’s size 10


  • Australian Men’s Sizes are the same as UK Men’s Sizes

    • For example, Australia Men’s size 10 = UK Men’s size 10

  • Australian Men’s Sizes are equal to one size down than USA Men’s Sizes

    • For example, Australia Men’s size 10 = USA Men’s size 11

  • UK Men’s Sizes are equal to one size down from USA Men’s Sizes

    • For example, UK Men’s size 10 = USA Men’s size 11


The size chart below is to be used as a rough guide only, as already noted, the best course of action in buying the correct size footwear is to measure your feet and seek out the specific manufacturers sizing guide. Reference any generic size guide charts as a sanity check only!

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Altra Lone Peak 5 for Women

Altra Lone Peak 5 for Men

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Wow, extremely comprehensive.

When I did the Marsthon des Sables they recommended going up 2 sizes minimum due to the heat induced swelling.

Angela Hart
Angela Hart

Yes, it was certainly an eye-opener for me, I can't believe I've been wearing the wrong size activity shoes for so long.

Was 2 sizes about right?

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