Shoe Size Converter: US to UK

Convert shoe sizes between US and UK instantly. Quick reference charts for men's, women's, and kids' sizes with foot length in cm and inches.

Convert from

Size

US 9 = UK 8.5

Foot length (cm)

27.5 cm

Foot length (in)

10.8 in

Shoe sizes can vary between brands and models. These conversions are based on standard sizing charts. We recommend checking the specific brand's size chart when possible.

How to measure your foot

Place a piece of paper on a hard floor against a wall.
Stand on the paper with your heel against the wall.
Mark the longest point of your foot (usually the big toe or second toe).
Measure the distance from the wall to the mark in centimeters.
Measure both feet and use the larger measurement.

Measure your feet at the end of the day when they are at their largest.

Men's US to UK Shoe Size Chart

US Size	UK Size	Foot (cm)	Foot (in)
3.5	3	22.0	8.7
4	3.5	22.5	8.9
4.5	4	23.0	9.1
5	4.5	23.5	9.3
5.5	5	24.0	9.4
6	5.5	24.5	9.6
6.5	6	25.0	9.8
7	6.5	25.5	10.0
7.5	7	26.0	10.2
8	7.5	26.5	10.4
8.5	8	27.0	10.6
9	8.5	27.5	10.8
9.5	9	28.0	11.0
10	9.5	28.5	11.2
10.5	10	29.0	11.4
11	10.5	29.5	11.6
11.5	11	30.0	11.8
12	11.5	30.5	12.0
13	12	31.0	12.2
14	13	31.5	12.4
15	14	32.0	12.6

Need to convert between more sizing systems?

Universal shoe size converter

Need US to EU conversion instead?

US ↔ EU shoe size converter

Need EU to UK conversion instead?

EU ↔ UK shoe size converter

Shoe Size Converter: US to EU Shoe Size Converter: EU to UK

US to UK shoe size converter. American to British shoe size conversion for men, women, and kids.

A US to UK shoe size converter translates between the American and British systems, both based on barleycorns but offset by different constants. It applies the standard rules — subtract 1 for men and 1 for kids, subtract 2 for women — and uses lookup tables to handle brand-level variations.

What Is a US to UK Shoe Size Converter?

A US to UK shoe size converter is a tool that translates shoe sizes between the American and British sizing systems. Both systems are based on barleycorns (one-third of an inch per size increment), but they use different starting points: for men, a US size is roughly 1 larger than the UK equivalent, and for women, the US size is 2 larger. A US men's 10 equals a UK 9, while a US women's 8 equals a UK 6.

Despite their shared barleycorn heritage, US and UK shoe sizes are not interchangeable. The British system originated in the 1800s and uses one unified scale for men and women, with size determined by the formula 3 times foot length in inches minus 23. The American system, formalized with the Brannock Device in 1927, adopted the same barleycorn unit but introduced separate scales for men and women — subtracting 22 for men and 21 for women instead of the British 23. This creates the characteristic offset: men differ by about 1 full size, and women by about 2.

This distinction matters most when buying from UK-based brands like Dr. Martens, Clarks, or shopping on ASOS — all of which list sizes in UK numbers. Our converter handles bidirectional conversion for men, women, and kids, so you can enter either a US or UK size and get the correct equivalent instantly.

How to Convert US Shoe Size to UK (and UK to US)

Converting between US and UK shoe sizes requires knowing the gender category because the US system uses separate scales for men and women, while the UK system traditionally uses one scale.

To convert US to UK shoe size:

1. For men's shoes, subtract 1 from your US size. A US men's 10 becomes a UK 9. Some premium shoemakers (such as Edward Green or Crockett & Jones) use a 0.5 offset instead, so check the brand's chart for high-end footwear.

2. For women's shoes, subtract 2 from your US size. A US women's 8 becomes a UK 6.

3. For kids' shoes, subtract 1 from the US size, similar to men's. A US kids' 3Y becomes a UK 2.

To convert UK to US shoe size:

1. For men, add 1 to the UK size. A UK 9 becomes a US men's 10.

2. For women, add 2 to the UK size. A UK 6 becomes a US women's 8.

3. For kids, add 1 to the UK size. A UK 2 becomes a US kids' 3Y.

These rules work reliably across most mainstream brands like Nike, Adidas, New Balance, Dr. Martens, and Clarks. For the most precise result, measure your foot length in centimeters and use that as the bridge between systems. Our converter above uses manufacturer-grade lookup tables for accuracy across the full size range.

US to UK Shoe Size Conversion Formula

UK = US_{men} - 1

$UK$ = UK shoe size (same scale for men and women)
$US_{men}$ = US men's shoe size
$US_{women}$ = US women's shoe size

Both the US and UK systems derive shoe size from foot length in inches using barleycorns (1 barleycorn = 1/3 inch). The formulas are:

US_{men} = 3 \times L_{in} - 22

US_{women} = 3 \times L_{in} - 21

UK = 3 \times L_{in} - 23

Where $L_in$ is foot length in inches. Comparing these formulas reveals the offset:

UK = US_{men} - 1

UK = US_{women} - 2

The difference comes from the constant each system subtracts. The UK uses 23 for everyone, the US uses 22 for men and 21 for women. Since both systems multiply by the same factor of 3, the offsets are exact: 1 size for men and 2 sizes for women.

For children, the US system subtracts a different constant (roughly 24.33) while the UK subtracts approximately 25.33, maintaining the same 1-size offset as men's shoes:

UK_{kids} = US_{kids} - 1

Note that some heritage British shoemakers use a half-size offset (0.5 instead of 1) for men's shoes. This discrepancy arises from variations in how manufacturers round and from differences between the Brannock standard and traditional British lasts. When in doubt, measuring foot length eliminates the ambiguity.

US to UK Shoe Size Conversion Examples

Ordering Dr. Martens Online (Men's US 10)

You wear a US men's 10 and want to buy Dr. Martens 1460 boots. Dr. Martens uses UK sizing exclusively — even on their US website, the primary size listed is UK. Applying the formula: UK = 10 - 1 = UK 9. On the Dr. Martens site, select UK 9. Keep in mind that Dr. Martens leather boots tend to run about a half size large and will stretch slightly after break-in. If you are between a US 9.5 and 10, a UK 9 may feel roomy after a few weeks of wear, and you could consider UK 8 with thicker socks.

Shopping on ASOS for Women's Shoes (US 8)

You wear a US women's 8 and want to order heels from ASOS, which lists all footwear in UK sizes. Applying the formula: UK = 8 - 2 = UK 6. Select UK 6 on the ASOS website. ASOS also shows the equivalent US size in their size chart, but the UK number is the one printed on the shoe itself. If you normally wear a US 8.5, select UK 6.5 on ASOS. For pointed-toe styles from European designers sold on ASOS, consider going up to UK 7, as narrow toe boxes can feel tighter.

Buying Clarks School Shoes for Kids (US 3Y)

Your child wears a US youth size 3 (3Y) and you are buying Clarks school shoes, which use UK sizing. Applying the kids' formula: UK = 3 - 1 = UK 2. Select UK 2 in the Clarks size guide. Children's feet grow approximately 1 to 2 sizes per year between ages 4 and 10, so many parents order one size up (UK 3) for extra growing room. Clarks offers a particularly useful in-store foot measuring service that accounts for both length and width, which is worth using if you have a Clarks store nearby.

Tips for Accurate US to UK Shoe Size Conversion

Remember the key offsets: subtract 1 for men (US 10 = UK 9), subtract 2 for women (US 8 = UK 6), subtract 1 for kids (US 3Y = UK 2). These three rules handle 95% of conversions.
Check whether a UK brand uses the standard offset or a half-size offset. Most mass-market brands (Dr. Martens, Clarks, Reebok UK) use the standard 1-size difference for men. Some premium Northampton shoemakers (Crockett & Jones, Church's, Edward Green) use only a 0.5 offset.
Dr. Martens are labeled in UK sizes even when sold in the US. The US size printed on the box is the converted number — always refer to the UK size first and apply your own conversion to avoid double-converting.
When ordering from ASOS, the shoe itself will be marked in UK sizes. The US conversion shown on the product page is an estimate. If you know your UK size from these formulas, use that directly.
Measure your foot in the afternoon when feet are at their largest. Stand with full weight on the foot and measure heel to longest toe. This foot length in centimeters is the universal reference if the offset formulas leave you uncertain.
If you are between sizes, round up. UK shoes that are slightly too large can be adjusted with an insole. UK shoes that are too small, especially leather ones like Dr. Martens or Clarks, will cause blisters during the break-in period.

Frequently Asked Questions: US to UK Shoe Size

What UK shoe size is a US 10?

A US men's 10 is a UK 9. A US women's 10 is a UK 8. The difference exists because the US system uses separate scales for men and women, while the UK traditionally uses one scale. For men, subtract 1 from the US size to get the UK size. For women, subtract 2. So US men's 10 minus 1 equals UK 9, and US women's 10 minus 2 equals UK 8.

What is a UK 8 in US shoe size?

A UK 8 equals a US men's 9 and a US women's 10. To convert UK to US, add 1 for men's shoes and add 2 for women's shoes. A UK 8 is a very common men's size in Britain, equivalent to a foot length of about 26.7 cm (10.5 inches).

What US size is a UK 7 in women's shoes?

A UK 7 is a US women's 9. To convert from UK to US women's sizes, add 2 to the UK number. UK 7 corresponds to a foot length of approximately 26 cm (10.24 inches). This is considered a medium-to-large women's size in both the US and UK markets.

What size Dr. Martens should I buy in UK if I wear US 9?

If you wear a US men's 9, order Dr. Martens in UK 8. Dr. Martens uses UK sizing as their primary system. Apply the standard men's formula: US 9 minus 1 = UK 8. Note that Dr. Martens boots, especially the classic 1460, tend to run slightly large and will stretch during break-in. If you are a solid US 9 without room to spare, UK 8 will be correct. If you are a loose US 9 or between 8.5 and 9, you could try UK 7.

Are US and UK shoe sizes the same for kids?

No. US kids' shoe sizes are approximately 1 size larger than UK kids' sizes, the same offset as men's shoes. A US kids' 10 equals a UK kids' 9, a US kids' 13 equals a UK 12, and a US youth 3Y equals a UK 2. Both systems use the barleycorn increment, and both restart numbering for larger children (the UK restarts at 1 after kids' size 13, the US does the same), but the US numbers are always about 1 higher.

Why is the US-to-UK offset different for men and women?

The offset differs because the US system created separate numbering scales for men and women, while the UK system uses one scale for both genders. In the US, the men's formula subtracts 22 from barleycorn length and the women's formula subtracts 21, producing a 1.5-size gap between US men's and women's numbers. The UK formula subtracts 23 for everyone. So men's US minus UK = 22 versus 23 = 1 size difference, and women's US minus UK = 21 versus 23 = 2 sizes difference.

Do Clarks shoes use US or UK sizing?

Clarks uses UK sizing as their native system. On the Clarks US website, both US and UK sizes are displayed, but the shoe itself is marked with the UK size. If you wear a US men's 10, select UK 9 in Clarks. For US women's 8, select UK 6. Clarks shoes generally fit true to size, and the brand offers width options (narrow, standard, wide) in both US and UK sizing, making them more accommodating than many European brands.

Is US to UK shoe size always exactly 1 size difference for men?

For most mainstream brands, yes — US men's = UK + 1. However, some premium British shoemakers use a half-size offset (US = UK + 0.5). Brands like Crockett & Jones, Church's, and Edward Green follow this smaller offset. The discrepancy exists because these heritage brands base their UK sizes on traditional lasts that predate the Brannock standardization. When shopping high-end British shoes, always check the brand's specific size guide rather than relying on the general formula.

Key Terms

Barleycorn

The unit of measurement used in both US and UK shoe sizing, equal to one-third of an inch (8.47 mm). Each full shoe size increment corresponds to one barleycorn of foot length. The name comes from the medieval English practice of using a grain of barley as a standard length.

Brannock Device

The standard foot-measuring tool used in US shoe stores since 1927, invented by Charles Brannock. It measures heel-to-toe length, arch length, and foot width, and produces sizes in the US/American scale. The Brannock system uses a different starting-point constant than the UK system, creating the offset between American and British sizes.

UK Sizing

The British shoe sizing system, which uses one unified scale for both men and women. Size is calculated as 3 times foot length in inches minus 23. UK sizing is the native system for brands like Dr. Martens, Clarks, Church's, ASOS own-brand shoes, and most footwear sold in the United Kingdom.

US Sizing

The American shoe sizing system, which uses separate scales for men and women. Men's size equals 3 times foot length in inches minus 22; women's equals the same calculation minus 21. This creates a 1.5-size gap between men's and women's US numbers for the same foot length.

Last

A three-dimensional mold shaped like a foot, around which a shoe is constructed. Different brands use different lasts, which is why a UK 9 in Dr. Martens may feel different from a UK 9 in Clarks. The shape of the last determines the shoe's fit, width, and proportions.

Half-Size Offset

A variation in US-to-UK conversion where the difference is 0.5 sizes instead of the standard 1 size for men. Used by some premium British shoemakers such as Crockett & Jones and Edward Green. Buyers of high-end British shoes should check whether the brand uses a 0.5 or 1.0 offset.

Width Fitting

A letter or descriptor indicating shoe width. In the UK, widths are typically labeled as narrow, standard (F for men, D for women), wide (G/H for men, E for women), and extra wide. The US uses letters like B (women's standard), D (men's standard), and EE (wide). Width designations do not change between US and UK sizing — only the length number converts.