Shoe Size Conversion

The Complications of Shoe Sizing

Shoe size is a complicated topic due to the lack of a global standard. Differences in the way shoe size is measured and determined in various countries, in the feet of men vs. women, in the way that different brands label and manufacture their shoes, and even the fact that individuals often have different sized feet, all contribute to the complication in finding a proper shoe size.

Much of the reason for a lack of a standard is due to shoe making having existed long before mass production; shoe makers had to make shoes individually, and thus would cater to the individual, wherever they may have been. This led to the development of many different methods of measurement, fabrication, and so on, and there was not enough motivation for different countries or even regions to collaborate and develop a standard.

Our calculator above estimates shoe size solely based on the foot length. While there are many other factors that impact overall shoe fit, which we will discuss below, our calculator seeks to provide a consistent reference through which a person can build a basis for identifying a shoe that is most likely to be a good fit.

Shoe Size Calculation Formulas

The following formulas demonstrate how different regions calculate shoe sizes based on foot length (L). Note that these are approximations.

Comprehensive Shoe Size Charts

Women's Shoe Size Chart

Men's Shoe Size Chart

Infant and Toddler Shoes (Age 0 - 4)

Kid's Shoes (Age 5 - 12)

Foot Measurement Systems

Shoe size estimation is based on the measurement of foot size. A given shoe size is a function of the manufacturer, the shoe last (the physical form used to manufacture and repair shoes), a country's standards, and more. There are numerous foot measurement systems including the Brannock device, the RITZ stick, and the Mondopoint system.

Brannock Device

The Brannock device is used to acquire three key measurements that impact proper fit: Foot length (heel to longest toe), Foot width (at the ball of the feet), and Arch length (heel to inside ball of the foot). Although this is the preferred device used by professionals, it does not measure all factors like the circumference of the ball of the foot or heel width.

RITZ Stick

The RITZ stick was the standard measuring device prior to the Brannock device. It is a wooden slide ruler with men's and women's shoe sizes and a conversion chart on the opposite side for converting between width and length.

Mondopoint System

The Mondopoint system is commonly used in the sports industry for athletic shoes like ski boots and skates, and is the primary system in countries like Russia, China, Japan, and South Korea. It is based on the average foot width and length (measured in millimeters), and also factors in the perimeter circumference of the foot around the metatarsophalangeal joints, generally allowing for better fitting than length-only systems.

How to Find the Right Shoe

Finding the right shoe can be difficult. Factors impacting shoe fit include Foot Length, Foot Width (though there is no real standard for width labeling), Foot Shape (circumference and arch position), Sex (men generally have broader feet and different arch shapes), Age (ligaments change over time), and the specific Manufacturer's design lasts.

Tips for measuring your foot: Measure your feet later in the day when they are slightly swollen. Use a Brannock device if possible. Always fit a shoe to your largest foot. It is generally better to have a shoe that is slightly loose rather than slightly tight, leaving room to accommodate swelling during long periods of wear.