So, what is going to determine how you use the ankle holster is the height of your boots. Now, there’s a certain amount of wiggle room, so to speak; exactly where the holster rides on you depends on the shape of your foot and so on. Therefore, you may find that your ankle holster sits a little lower of higher than it does on someone of the same height and shoe size.
That said, let’s briefly discuss boot length and how that’s measured.
Boot height is measured by the insole to the top of the boot shaft in pull-on boots. It’s different, however, for lace-ups.
Lace-up boots are usually 1 inch shorter than pull-on boots that are said to have the same shaft length because the length is measured by the eyelets rather than shaft height. So, a 6-inch lace-up boot actually has a 5-inch boot shaft, but the strip of eyelets will be 6 inches long in total.
Since eyelets are almost universally 1 inch apart, that means a 6-eyelet boot is a 6-inch boot, an 8-eyelet boot is 8 inches and so on and so forth.
This is for standard lacing. If you wear semi-lace-to-toe or lace-to-toe boots, the length will be the height from the insole plus one inch.
So, what sort of boots are people likely to wear?
Typically, people who wear fashion boots in the office setting will wear 6-inch boots. These are a good middle ground between sturdy footwear – often needed in winter – and comfort, especially if you don’t want your feet to boil once you get in from the cold. Pull-on boots (such as the Chelsea boot style) will usually be 6 inches in height, 6-inch lace-ups will have a 5-inch shaft.
Some people wear 6-inch work boots, but 8-inch work boots tend to be more common for those who labor out of doors or those who wear duty boots such as law enforcement or security personnel. Those in the logging industry and linesmen will usually have 10-inch or taller lace-up boots.
Source: Alien Gear Holsters