some British shoe manufacturers are typically based on the width of the foot, and common step sizes are inch (4.8 mm). Difficulties There could be differences between various shoe size tables from shoemakers and shoe stores. They are usually due to the following factors: Different methods of measuring the shoes, different manufacturing processes, or different allowances even when the same system is used. An indication in centimetres or inches can mean the length of the foot or the length of the shoe's inner cavity. Differing amounts of wiggle room required for different sizes of shoes. For wide feet, a shoe several sizes larger (and actually too long) may be required and may also result in inconsistent size indications when different typical widths are attributed to specific shoe sizing systems. Some tables for children take future growth into account. The shoe size is then larger than what would correspond to the actual length of the foot. Conversion tables available on the Web often contain obvious errors, not taking into account different zero points or wiggle room. Although shoe size systems are not fully standardised, the ISO/TC 137 had released a technical specification ISO/TS 19407:2015 for converting shoe sizes across various local sizing systems. Even though the problem of converting shoe sizes accurately has yet to be fully resolved, this standard serves as "a good compromise solution" for shoe-buyers. Common sizing systems United Kingdom Shoe size in the United Kingdom, Ireland, India, Pakistan and South Africa is based on the length of the last used to make the shoes, measured in barleycorns ( inch) starting from the smallest size deemed practical, which is called size zero. It is not formally standardised. Note that the last is typically longer than the foot heel to toe length by to in or to 2 barleycorns, so to determine the shoe size based on actual foot length one must add 2 barleycorns. A child's size zero is equivalent to 4 inches (a hand = 12 barleycorns = 10.16 cm), and the sizes go up to size (measuring barleycorns, or ). Thus, the calculation for a children's shoe size in the UK is: equivalent to: . An adult size one is then the next size up (26 barleycorns, or ) and each size up continues the progression in barleycorns. The calculation for an adult shoe size in the UK is thus: equivalent to: . Although this sizing