Wedding Garter Advice Request

I don't sew very often but have just half made a couple of experimental wedding garters. They aren't for anyone in particular I was just curious to know how to make them. My trouble is I can't seem to find a standard measurement to finish them off, horse riding and manual labour mean I'm not a good template so does anyone have a standard measurement so I can finish off the main body of the garters and start having fun with the embellisments please :)