Free US to UK Shoe Size Converter

US to UK Shoe Size Conversion Made Simple

When shopping for footwear from British brands, converting a US shoe size to its UK equivalent is essential for a correct fit. Although both sizing systems are based on foot length, they apply different formulas and constants. This free online American to British shoe size calculator acts as a reliable shoe size converter, handling the math instantly so you can focus on finding the perfect pair of shoes.

The Formulas Behind the Numbers

Both US and UK sizes start from the foot length measured in inches. A linear multiplier of 3 is used, followed by region‑specific subtraction constants that vary by gender and age.

United States (based on foot length in inches):

$$\text{Men: } \text{US} = 3 \times (\text{foot length}) - 22$$ $$\text{Women: } \text{US} = 3 \times (\text{foot length}) - 21$$ $$\text{Child: } \text{US} = 3 \times (\text{foot length}) - 9.67$$

United Kingdom (based on foot length in inches):

$$\text{Adult (men and women same): } \text{UK} = 3 \times (\text{foot length}) - 23$$ $$\text{Child: } \text{UK} = 3 \times (\text{foot length}) - 10$$

A notable difference: the US maintains separate scales for men and women (a woman’s size is one number higher than a man’s for the same foot length), while the UK uses a single adult scale for both genders. The formulas for children also diverge slightly between the two systems.

Measuring Your Foot at Home

You can determine your US or UK size without a fitting device by following these steps:

1. Place your bare foot flat on a sheet of paper and mark the back of the heel and the tip of the longest toe.
2. Measure the distance between the two marks in inches (or in millimeters and convert).
3. Apply the appropriate formula above, or enter the length directly into the converter for instant results.

If you already know your US or UK size, you can skip the measurement and use the direct conversion rules or the calculator.

Direct Conversion Between US and UK Sizes

For adults, a simple additive relationship applies:

• US men’s size = UK size − 1
• US women’s size = UK size − 2

The table below illustrates common conversions from UK to US:

UK Size	US Men	US Women
5	4	3
6	5	4
7	6	5
8	7	6
9	8	7
10	9	8
11	10	9

For children, the offset is fractional rather than integer. Based on the foot‑length formulas, the US child size is approximately 0.33 sizes larger than the corresponding UK child size:

$$\text{US child} \approx \text{UK child} + 0.33$$

Because of this fraction, using the converter or the original foot‑length formulas is recommended for accurate children’s conversions.

How the Converter Works

Using the tool requires only a few clicks:

• Select whether you are converting for an adult or a child.
• Enter a US shoe size to see its UK equivalent, or type a UK size to obtain the US size.
• Alternatively, provide foot length in inches or millimeters, and the calculator will compute both US and UK sizes automatically.

The converter also displays corresponding values for other global systems, such as European (EU) and Korean standards. This makes it an all‑in‑one resource for anyone dealing with multiple sizing systems, whether ordering shoes online or checking fit while traveling abroad.