the size chart be at -lrb- ... -rrb- -lrb- scroll down that web page to the Aqua Fitness Gloves section -rrb- . accord to my reading of the chart : 8cm palm width = small 8.5 cm = medium 9-9 .5 cm = large 10-10 .5 = xl . to use the size chart i measure the horizontal width of my palm start from where the thumb meet the palm . my palm measure 9.5 cm and the glove that arrive -lrb- size large -rrb- fit , but a little snug . so i think i read the chart correctly , since accord to the chart my hand be at the upper end of the size large . I do not mind the snugness at all , except there be a little too much pressure in the crevice between my index and middle finger . it be not uncomfortable enough to return the product . in all other respects the product fit well , be comfortable , and seem very well make . i have never use swim glove before . i expect they would produce more resistance in the water than they actually do . so i do not know how much they will increase the strength building i be hope to accomplish by use they while swim . give how difficult the seller and manufacturer make it to figure out what size glove to purchase , the discomfort between my index and middle finger , and the limited use the glove probably will have , i only give the product 3 star . if i be to rate the product purely on the quality and strength of the material i would probably give it 5 star , and if my only issue be the discomfort between the two finger i would give it no less than 4 start .