CHAIN LENGTH GUIDE
A chain that’s too short can make your neck look overly bulky if you have a larger build. If you have a smaller frame, a tight chain can give your features a thinner and weaker look.
On the other hand, on someone who’s smaller in stature, a chain that is too long will look oversized. Those with a larger frame may look a bit more heavyset if their chain hangs too low.
CHOOSE THE RIGHT FIT
The key is to find a good length in between too short and too long. Your personal preference and style also play a big role in what length you choose. Some people like to wear very short chains (chokers) and some may like chains that hang down low. That may not be the most common but it's their style so they can rock them like that. At the end of they day its about expressing yourself which you can do however you'd like.
This picture gives you an idea of what a 20", 24" and 28" chain will look like. If the length of the chain you want isn't shown here, use this as a guide line to get an estimate of how much longer or shorter it will be compared to one shown here.
Keep in mind, a 20" chain won't look the same on everyone. The same size chain will dangle down further on somebody who's smaller compared to someone much larger. The man in this picture will most likely have a larger neck and be taller than you. With that being the case, the same length chains will go further down on you. Some things that will affect how far the chain goes down on you is your neck size, your height and if the chain as a pendant or not (pendant will make the chain sit a bit lower).
(Model - 6'2" or 188cm wearing 3mm Cuban Chains)