Your boots say 42, your cart says size 9. One wrong guess means a blister on day two or a return label on day ten. Type a foot length or any size into the shoe size calculator below and get every system at once.
TL;DR: Enter a foot length or any size to get US, UK, EU, Japan and Mondopoint/CN sizes for men, women and kids. Treat every result as a close guide, because brands differ.
Shoe Size Calculator
Turn a foot measurement or any shoe size, for men, women or kids, into US, UK, EU, Japan and Mondopoint sizes.
Calculator
Your measurement
Sizes 1 to 7 exist in both stages, so pick the stage printed on the shoe or box.
Adds 0.5 cm plus 0.25 cm per step to your measured length before US, UK and EU sizes are calculated. Mondopoint and Japan/CM still show your measured foot length. Some charts and brands already include room for the foot, so the allowance may overlap.
For kids, standard sizes already include growing room, so keep this Off unless you want extra room.
Results
Running wide or narrow? Hiking footwear often fit true-to-length but tight/loose through the WIDTH, check reviews for this specific model on outdoortrekker.com
Shoe Size Conversion Chart: EU, US, UK, CN and Centimeters
To convert a shoe size, match your foot length to the chart below. Every system maps to the same length, so this shoe conversion chart is built on foot length, not brand labels.
Shoe size conversion chart: EU 36 to 47 with US, UK, CN and foot length
| EU | Men’s US | Women’s US | UK | Foot cm | Foot in | CN / Mondopoint (mm) |
|---|---|---|---|---|---|---|
| 36 | 5 | 6 | 4 | 22.7 | 8.92 | 227 |
| 37 | 5.5 | 6.5 | 4.5 | 23.3 | 9.19 | 233 |
| 38 | 6.5 | 7.5 | 5.5 | 24.0 | 9.45 | 240 |
| 39 | 7 | 8 | 6 | 24.7 | 9.71 | 247 |
| 40 | 8 | 9 | 7 | 25.3 | 9.97 | 253 |
| 41 | 8.5 | 9.5 | 7.5 | 26.0 | 10.24 | 260 |
| 42 | 9.5 | 10.5 | 8.5 | 26.7 | 10.50 | 267 |
| 43 | 10.5 | 11.5 | 9.5 | 27.3 | 10.76 | 273 |
| 44 | 11 | 12 | 10 | 28.0 | 11.02 | 280 |
| 45 | 12 | 13 | 11 | 28.7 | 11.29 | 287 |
| 46 | 12.5 | 13.5 | 11.5 | 29.3 | 11.55 | 293 |
| 47 | 13.5 | 14.5 | 12.5 | 30.0 | 11.81 | 300 |
Brand charts can differ, especially around EU 40 and 41. Nike, for example, pairs men’s 8 with EU 41. When in doubt, check the brand’s own chart.
Pro-Tip: Between two sizes? Go larger for hiking footwear, smaller for street shoes. Hiking boots need toe room on descents. Street shoes do not.
EU to US Shoe Size (Men’s and Women’s)
European shoe size conversion to US depends on the US scale you use. Women’s comes first, since euro shoe size to US women’s is the most common lookup.
What size is 41 in US? EU 41 is women’s US 9.5 and men’s US 8.5. That equals UK 7.5, for a foot about 26.0 cm (10.24 in) long.
Size 40 shoes in US: EU 40 is women’s US 9 and men’s US 8. That equals UK 7, for a foot about 25.3 cm (9.97 in) long.
US to EU Shoe Size (Size 11 in EU)
US to EU shoe size also depends on the scale. Size 11 in EU: men’s US 11 is EU 44 (UK 10, foot 27.9 cm). Women’s US 11 is EU 42.5 (UK 9, foot 27.1 cm). EU counts in finer steps than US, as the sizing systems section explains.
Chinese (CN) Shoe Size to US
A CN shoe size is Mondopoint, the foot length in millimeters. So a Chinese shoe size to US conversion is direct: read the number as millimeters and find the row in the CN column above. China’s GB/T 43293-2022, modified from ISO 9407:2019, requires the size to include foot length in millimeters. GB/T 36935-2018 covers CN, UK, US and EU conversions. Take CN 250. That is a 250 mm foot, which is men’s US 7.5, women’s US 8.5, UK 6.5 and EU 39.5.
One trap: some sellers print EU-style numbers. Values from about 220 to 300 are millimeters. Values from about 35 to 47 are EU-style.
Men’s to Women’s Shoe Size: 7.5 Women’s to Men’s and More
A women’s size converts to a men’s size by subtracting 1 or 1.5, depending on the brand. Nike charts subtract 1.5. Adidas and New Balance charts subtract 1, and so does our calculator.
7.5 women’s to men’s: men’s 6 on Nike charts, and men’s 6.5 on adidas, New Balance and calculator results.
Size 9 in men to women: women’s 10.5 on Nike charts, and women’s 10 on adidas, New Balance and calculator results.
Brands follow their own conventions, so no rule is universal. Trust the brand’s chart for that brand, and the calculator when you start from foot length.
Women’s to men’s shoe size, two rules side by side
| Women’s US | Men’s US (Nike, 1.5 gap) | Men’s US (adidas, New Balance, calculator, gap of 1) |
|---|---|---|
| 6 | 4.5 | 5 |
| 7 | 5.5 | 6 |
| 7.5 | 6 | 6.5 |
| 9 | 7.5 | 8 |
| 11 | 9.5 | 10 |
Kids’ Shoe Size Chart (US, UK, EU and Inches)
This US kids shoe size chart covers baby to big kids, with foot length in inches and cm plus UK and EU sizes. C rows come first, then Y rows.
Kids shoe size chart US: C and Y sizes in inches and cm, with UK and EU
| US | Foot in | Foot cm | UK | EU |
|---|---|---|---|---|
| 1C | 3.58 | 9.1 | 1 | 15.5 |
| 2C | 3.92 | 9.9 | 2 | 17 |
| 3C | 4.25 | 10.8 | 3 | 18 |
| 4C | 4.58 | 11.6 | 4 | 19.5 |
| 5C | 4.92 | 12.5 | 5 | 20.5 |
| 6C | 5.25 | 13.3 | 6 | 22 |
| 7C | 5.58 | 14.2 | 7 | 23.5 |
| 8C | 5.92 | 15.0 | 8 | 24.5 |
| 9C | 6.25 | 15.9 | 9 | 26 |
| 10C | 6.58 | 16.7 | 10 | 27 |
| 11C | 6.92 | 17.6 | 11 | 28.5 |
| 12C | 7.25 | 18.4 | 12 | 29.5 |
| 13C | 7.58 | 19.3 | 13 | 31 |
| 1Y | 7.92 | 20.1 | 1 (junior) | 32 |
| 2Y | 8.25 | 21.0 | 2 (junior) | 33.5 |
| 3Y | 8.58 | 21.8 | 3 (junior) | 34.5 |
| 4Y | 8.92 | 22.6 | 4 (junior) | 36 |
| 5Y | 9.25 | 23.5 | 5 (junior) | 37 |
| 6Y | 9.58 | 24.3 | 6 (junior) | 38.5 |
| 7Y | 9.92 | 25.2 | 7 (junior) | 40 |
Brand charts such as Nike’s often list UK half a size below US for kids, while this chart shows them equal. The gap is within half a size, so check the brand’s chart.
C vs Y: How Kids’ Shoe Sizes Work
US and UK kids sizes run from 0 to 13.5, then restart at 1. So “size 3” can mean a toddler’s 3C or a big kid’s 3Y. EU and Mondopoint never restart. US youth sizes are unisex.
Label every size C or Y, not with age words. Standard kids sizes already include room to grow, so add nothing extra.
Big Kids Shoe Size Chart
Big kids sizes are the Y sizes, 1Y to 7Y above. Seven is the top of youth sizing. Retailers split little and big kids in different places, some at 13.5C and others at 3Y.
Little Kids Shoe Size Chart
Little kids sizes sit in the upper C rows, up to the restart at 1. Find your child’s foot length in those rows and read across.
Kids Shoe Size Chart by Age
Age is only a rough guide, because children grow at different rates. Measure the longer foot and choose the size from its length.
Kids Shoe Sizes to Women’s
Nike’s youth numbers follow men’s numbers, and its women’s sizes sit 1.5 above. So 5Y is women’s 6.5 and 7Y is women’s 8.5. That rule is Nike’s.
Nike and Adidas Kids Size Charts
In our tests against published charts, Nike’s baby to little sizes tracked the standard closely, with the biggest gaps in the top youth sizes. For Adidas, use the brand’s own chart.
Pro-Tip: Thumb check. Leave about a thumb’s width in front of the longest toe while the child stands.
How to Measure Shoe Size at Home (Inches and Foot Size in cm)
How to measure foot size in cm: stand on a sheet of paper against a wall, mark your longest toe, then measure from the wall to the mark in centimeters. Measure both feet and use the larger number.
- Tape paper to a hard floor, one edge against a wall.
- Stand on it, heel to the wall, weight on the foot.
- Mark your longest toe, which is not always the big toe.
- Measure from the wall to the mark.
- Repeat with the other foot and use the larger number.
To convert, divide centimeters by 2.54 for inches, or multiply by 10 for millimeters. Then enter the result in the shoe size calculator.
Pro-Tip: Measure at the end of the day, in the socks you will wear. Feet swell through a day and more over a long hike. A morning measurement in thin socks can mislead you.
How Shoe Sizing Systems Differ (And Why Charts Disagree)
Three units cause most of the confusion. The Paris point is the EU step, worth 2/3 cm. The barleycorn is the US and UK step, worth 1/3 inch. Mondopoint is the foot length in millimeters, defined by ISO 9407. ISO/TS 19407 adds conversion tables between systems. Charts disagree because each source starts from a different base and rounds differently. Published rules even disagree on how UK and US sizes relate. Calculators use published formulas, so results are close guides. Ours rounds to the nearest half size, ties up.
Brands add more variation. Each builds on its own last, the foot-shaped mold behind the shoe. Heel-to-ball distance matters too: two feet of equal length can need different sizes, and a length-only tool cannot see that.
Shoe Width: What D, E and Wide Really Mean
Width is a separate decision from length. Converting a size does not change it, and our calculator has no width input by design.
Brannock devices measure width in letters from A to E, and fitters often mention EE. Kids’ fittings run E to H at Clarks and D to H at Start-Rite.
| Letters | Meaning | Typical sign |
|---|---|---|
| A, B | Narrower (B is the usual women’s standard) | Heel slips, foot slides sideways |
| C, D | Medium (D is the usual men’s standard) | Few width problems |
| E, EE | Wider | Pressure on the outer ball, foot spilling over the sole, numb toes on descents |
Running wide or narrow? Hiking footwear often fit true-to-length but tight/loose through the WIDTH, check reviews for this specific model on outdoortrekker.com
Pro-Tip: Hot spots beat the tape measure. A red patch on the outer ball of the foot after a hike points to width, not length. Fix it with a wider fit, not a bigger size.
Sizing Hiking Boots and Trail Shoes
Fit decides hiking comfort more than the number on the box. Try boots on an incline in the socks you plan to hike in, lace for a locked heel, and check that your toes stay off the front on a downhill.
If you do not know your pack weight, the Backpack Weight Calculator gives you a number to test with.
The harder the route, the more fit matters. A trail that scores high on the Hiking Difficulty Calculator will punish a slightly tight boot, because steep descents drive the toes forward.
These tips come from trail experience, not a standard.
Pro-Tip: Test boots on a ramp with a loaded pack. If your toes touch the front on the downhill, the boot is too small for the trail.
FAQ
What is size 41 in US?
EU 41 is women’s US 9.5 and men’s US 8.5 (UK 7.5, foot 26.0 cm).
What is size 40 in US shoes?
EU 40 is women’s US 9 and men’s US 8 (UK 7, foot 25.3 cm).
What is size 11 in EU?
Men’s US 11 is EU 44. Women’s US 11 is EU 42.5.
How do I convert women’s to men’s shoe size?
Nike charts subtract 1.5, while adidas, New Balance and our calculator subtract 1. So women’s 7.5 is men’s 6 or 6.5.
What is a CN shoe size in US?
A CN size is Mondopoint, the foot length in millimeters. CN 250 is men’s US 7.5 and women’s US 8.5.
How do I measure foot size in cm?
Mark your longest toe and heel on paper, then measure the distance in centimeters. Use the larger foot.
What is a big kids shoe size? Is it the same for boys and girls?
Big kids sizes are 1Y to 7Y, and US youth sizes are unisex.
Do Nike and Adidas kids sizes match the chart?
Nike tracks the standard chart closely at baby to little sizes, with gaps at the top of youth sizes. For Adidas, use the brand’s own chart.
Ethan Marlowe is an experienced hiker and outdoor gear specialist based in Colorado. With over 7 years of hands-on experience trekking through the Rockies, Pacific Northwest, and East Coast trails, he delivers practical advice, expert gear reviews, and survival insights. His goal is to help hikers of all levels make smarter decisions on and off the trail.
