Altra Size Guide
Altra is a running and trail footwear brand known for innovative shoe design centred on the concept of "FootShape Fit"—shoes built to accommodate the natural shape of the human foot rather than forcing the foot into a tapered shape. Altra offers a comprehensive range of shoes for road running, trail running, hiking, and everyday wear, alongside apparel lines for men and women. The brand is committed to true-to-size fitting across its shoe range, though fit can vary slightly by model. Whether you're a seasoned ultramarathoner or a casual walker, Altra provides detailed sizing guidance to ensure the perfect fit.
How to Measure
To find your correct Altra shoe size, measure your foot length and add 0.5 cm for proper toe space. Measure your feet at the end of the day when they are slightly swollen for the most accurate result. If your feet are different sizes, use the measurement of your larger foot.
- Position a piece of paper on a hard, flat floor next to a wall.
- Step onto the paper with your heel lightly touching the wall behind it.
- Mark the end of your big toe and the outermost part of your heel on the paper.
- Repeat the process with your other foot.
- Measure the distance between the two markings (heel to toe) for both feet.
- Add 0.5 cm to your measurement to ensure adequate toe space.
- Compare your final measurement to the foot length column in the appropriate size chart below.
Women's Altra Shoes
| UK Size | US Size | EU Size | Foot Length (cm) |
|---|---|---|---|
| 3.5 | 5.5 | 36 | 22 |
| 4 | 6 | 37 | 22.5 |
| 4.5 | 6.5 | 37.5 | 23 |
| 5 | 7 | 38 | 23.5 |
| 5.5 | 7.5 | 38.5 | 24 |
| 6 | 8 | 39 | 24.5 |
| 6.5 | 8.5 | 40 | 25 |
| 7 | 9 | 40.5 | 25.5 |
| 7.5 | 9.5 | 41 | 26 |
| 8 | 10 | 42 | 26.5 |
| 8.5 | 10.5 | 42.5 | 27 |
| 9 | 11 | 43 | 27.5 |
| 9.5 | 11.5 | 44 | 28 |
| 10 | 12 | 44.5 | 28.5 |
| 11 | 13 | 46 | 29.5 |
Men's Altra Shoes
| UK Size | US Size | EU Size | Foot Length (cm) |
|---|---|---|---|
| 6 | 7 | 40 | 25 |
| 6.5 | 7.5 | 40.5 | 25.5 |
| 7 | 8 | 41 | 26 |
| 7.5 | 8.5 | 42 | 26.5 |
| 8 | 9 | 42.5 | 27 |
| 8.5 | 9.5 | 43 | 27.5 |
| 9 | 10 | 44 | 28 |
| 9.5 | 10.5 | 44.5 | 28.5 |
| 10 | 11 | 45 | 29 |
| 10.5 | 11.5 | 46 | 29.5 |
| 11 | 12 | 46.5 | 30 |
| 11.5 | 12.5 | 47 | 30.5 |
| 12 | 13 | 48 | 31 |
| 13 | 14 | 49 | 32 |
| 14 | 15 | 50 | 33 |
| 15 | 16 | 51.5 | 34 |
Kids' Altra Shoes (Ages 4–12)
| UK Size | US Size | EU Size | Foot Length (cm) |
|---|---|---|---|
| K12 | 12.5 | 30 | 18.4 |
| K13 | 13 | 31 | 19.1 |
| K13.5 | 13.5 | 31 | 19.4 |
| 1 | 1 | 32 | 19.7 |
| 1.5 | 1.5 | 33 | 20.3 |
| 2 | 2 | 33 | 20.6 |
| 2.5 | 2.5 | 34 | 21 |
| 3 | 3 | 34 | 21.6 |
| 3.5 | 3.5 | 35 | 21.9 |
| 4 | 4 | 36 | 22.2 |
| 4.5 | 4.5 | 36 | 22.9 |
| 5 | 5 | 37 | 23.2 |
| 5.5 | 5.5 | 37 | 23.5 |
| 6 | 6 | 38 | 24.1 |
Men's Altra Apparel
| Size | Chest (inches) | Waist (inches) | Hips (inches) |
|---|---|---|---|
| Small | 34.5–37.5 | 28.5–31.5 | 34.5–37.5 |
| Medium | 37.5–40.5 | 31.5–34.5 | 37.5–40.5 |
| Large | 40.5–43.5 | 34.5–37.5 | 40.5–43.5 |
| X-Large | 43.5–47 | 37.5–41 | 43.5–47 |
Women's Altra Apparel
| Size | Bust (inches) | Waist (inches) | Hips (inches) |
|---|---|---|---|
| X-Small | 29–32 | 23–26 | 32–35 |
| Small | 32–35 | 26–29 | 35–38 |
| Medium | 35–38 | 29–32 | 38–41 |
| Large | 38–41 | 32–35 | 41–44 |
Product-Specific Guidance
Trail Running Shoes
Altra's trail running collection includes models such as Lone Peak and Superior, designed for off-road terrain with reinforced toeboxes and protective midsoles. Trail shoes should fit snugly at the heel with enough room in the forefoot to accommodate natural foot splay during descent. True-to-size fitting is recommended; however, if you run with thicker socks or have a wider forefoot, consider trying half a size up.
Road Running Shoes
Altra's road running range features lightweight, responsive models ideal for daily training and racing. Road shoes run true-to-size and are designed with a spacious, zero-drop platform that accommodates various foot shapes. If you transition from traditional running shoes with a heel drop, you may find road Altra shoes feel more spacious in the midfoot and toebox—this is intentional and supports natural running form.
Hiking and Outdoor Footwear
Hiking shoes combine the comfort of everyday wear with durability for rougher terrain. Altra hiking shoes feature water-resistant uppers and protective toe guards. Measure your feet carefully and wear the socks you plan to hike in during fitting. A snug heel fit prevents blisters during long descents, whilst generous toebox room reduces pressure on the toes.
Apparel — Fit Notes
Altra apparel is designed for active runners and trail athletes, offering both fitted and relaxed cuts. Chest measurements are taken at the fullest part of the chest; waist measurements at the natural waist; hip measurements at the fullest part of the hips. If your measurements fall between two sizes, choose the larger size for comfort during movement and layering.
Sizing Tips
- Always measure your feet at the end of the day when they are slightly swollen, as this reflects how they will feel during actual running or hiking activity.
- Add 0.5 cm to your foot-length measurement to ensure proper toe space—your toes should not touch the end of the shoe.
- If your left and right feet are different sizes, use the measurement of your larger foot to avoid discomfort.
- Altra shoes run true-to-size; however, fit can vary slightly by model. If a particular model feels tight or loose compared to other Altra shoes you own, consult model-specific sizing guidance on the Altra website.
- Wide-footed runners may benefit from Altra's dedicated "Wide Shoes" collection, which offers additional forefoot room while maintaining the brand's characteristic spacious toebox design.
- When trying on Altra shoes in-store or ordering online, wear the type of socks you plan to run in. Thicker socks or compression socks can affect fit.
- Altra shoes are designed for the natural shape of the foot, so they may feel wider and more spacious than conventional running shoes, especially in the midfoot and toebox—this is not a sizing error but a design feature.
- If you need to return or exchange your Altra purchase, most retailers offer hassle-free returns within 30–100 days, depending on the seller.