Shoe Size Conversion Calculator

Place a piece of paper on a hard floor and stand on it with your heel against a wall. Trace the outline of your foot. Measure from the heel mark to the tip of your longest toe (this is often the second toe, not the big toe). Measure both feet as they are rarely identical. Feet swell during the day, so measure in the afternoon or evening for the most accurate fit. Find the measurement in a size chart: add about 0.5 cm to your foot length for a comfortable fit allowance.

US and UK sizes are based on barleycorn units (1/3 inch increments), while EU sizes are based on Paris points (2/3 cm increments). These different base units produce the numeric offset you see in conversion charts. Because 1/3 inch does not equal 2/3 cm, the scales do not align perfectly and conversion charts contain rounding at some points. This is why converting between systems always produces approximate matches rather than exact equivalents.

In the US system, women's sizes run about 1.5 to 2 sizes larger than men's for the same foot length. A women's US 9 corresponds to approximately a men's US 7.5. In the EU system, size numbers are the same across genders: EU 38 for a woman and EU 38 for a man represent the same foot length. UK sizes also differ by gender: women's UK sizes run about 2 sizes larger than men's UK sizes for the same foot.

No single global standard governs shoe sizing. Each brand designs its shoes around a "last" (the foot-shaped form) that reflects its target customer's foot shape, not just length. Lasts vary in width, arch position, toe box shape, and heel depth. A size 10 from one brand may fit identically to a 9.5 or 10.5 from another. Athletic shoes built for narrow racing feet fit differently from casual shoes designed for everyday comfort. Always check brand-specific sizing guides or try shoes on when possible, especially when ordering online from an unfamiliar brand.

If you fall between two sizes, it is generally better to size up rather than down, especially for closed-toe shoes where cramping the toes causes long-term discomfort. For athletic shoes, many runners size up by half a size to allow for foot swelling during exercise. Using insoles or thick socks can help fill the small extra space in a half-size larger shoe. If one foot is larger than the other (common), fit to the larger foot.