Brannock device

The Brannock device is the metal foot-measuring tool invented by Charles Brannock in 1925, manufactured by the Brannock Device Company in Liverpool, NY. Used by virtually every US shoe store. Measures three dimensions: heel-to-toe length, heel-to-ball length (where the arch flexes), and ball width.

US shoe sizes increment in steps of one barleycorn — an English unit equal to ⅓ inch, in use since the 14th century. A US men’s size 10 has a foot length of ~10⅔ inches; each size up adds ⅓ inch. Women’s sizes use the same physical step but are labelled 1.5 numbers higher (a women’s 11.5 is the same foot length as a men’s 10), for historical reasons that no longer have any fitting rationale.

The Brannock device produces accurate foot measurements; the fit of any specific shoe still varies by brand and last shape. Convert any Brannock-derived US size to UK/EU/JP via our shoe size converter.

Worked example

A foot measures 10⅔ inches heel-to-toe under load. Each US size step is ⅓ inch (one barleycorn), with US men’s size 1 calibrated to a 7⅔-inch foot. So 10⅔ − 7⅔ = 3 inches above the size-1 reference, divided by ⅓ inch per size = 9 sizes above, giving US men’s size 10. The same foot in women’s sizing adds the conventional 1.5 offset → women’s 11.5. In UK sizing the reference is offset differently (UK starts a half-size lower than US for men), giving UK 9.5. In EU sizing, which uses the Paris point (⅔ cm per step) and runs continuously across genders, the same 10⅔-inch (271 mm) foot maps to roughly EU 43. The Mondopoint label for the same foot is simply “271”, the length in millimetres — no gender, no offset, no barleycorn arithmetic.

When and why it matters

The Brannock matters whenever shoe sizes refuse to translate cleanly across brands or geographies. A Nike US 10 fits differently from a Vans US 10 because the brand-specific last shape varies, but a Brannock measurement of your foot length is invariant — it’s the input you can take to any size chart. The most common fitting mistake is measuring sitting (no load), which under-reports foot length by ~5% and produces shoes a half-size too small. The second mistake is measuring only one foot — for ~60% of people the two feet differ by half a size, and the shoe must fit the larger one. The third is measuring children once and assuming the result holds; foot growth in children under 6 averages a half size every 3-4 months, which is why parents accumulate shoes faster than expected. Reference: Brannock Device Company — How to fit.

How to measure properly on a Brannock: stand (don’t sit) with full weight on the foot — your foot lengthens under load by roughly 5%. Wear the sock you intend to wear in the shoe. Slide the heel cup snug against the back of your heel, drop the length slider to the longest toe (not necessarily the big toe — Morton’s toe means the second is longer in ~20% of feet), then read the ball-length slider on the inside. The size to buy is the larger of the two readings, since a shoe’s flex point must align with the ball of your foot or the upper will crease badly.

Why the men’s/women’s offset is 1.5 in the US but 2 in the UK: the convention dates to a time when women’s shoes used a different last and the offset compensated for the geometry, not the foot. Modern unisex sneakers ignore this entirely and quote both numbers — a women’s 9 Air Force 1 is a men’s 7.5 in the same physical shoe. The Mondopoint system avoids the mess by labelling shoes in millimetres of last length and is mandatory for military and ski boots.