The best way to measure your ears' size for huggie hoops is to simply hold a ruler against your ear and measure the distance between the piercing and the edge of the ear. Make sure to measure both the ears; sometimes, the spacing between one ear is larger than the other. Remember that every ear and piercing is different. Also, the holes on the earlobes are larger than the second or third piercings in most cases.
When purchasing online, the most important thing to look for is the earrings' inner diameter given in the product description. For a snug fit, add 1mm to the inner diameter. For a loose fit, add 2mm or more. 10 millimeters make 1 centimeter.
1) Measure from the hole to the end of your earlobe with a ruler or a string.
2) Add 1mm for a snug-fitting hoop
3) Add 2mm or more for a loose comfy fitting hoop