shape of the stow last is short and wide ... closest US thing is the trubalance i think, but the aldens are longer for the same volume of the interior. my guess would be US 10.5 trubalance is closest to UK 10.5 stow, but YMMV brannock device says 10 UK = 10.5 US if your foot is more long than fat, go down 1/2 size for UK conversion. i.e., if 10.5 US, get a 10 UK stow. if your foot is more fat than long, go down 1 size for UK conversion. shoes will probably fit you best as that is the shape of the last. if 10.5 US, get a 9.5 UK stow. err on the side of big .. these are country boots ... i wear them all winter in snow and ice ... thick wool socks are ideal ... they make your feet 1/2 size bigger you would not wear the stows much in the summer unless you like hot feet ... so do not size for thin dress socks everyone's feet and fitting taste is different ... do not panic if you think you ordered wrong ... wait and see ... i ordered my barrie size (10.5 barrie, 10.5 UK stow) as i wear stows in much the same conditions as i wear the barrie boots