How long should a necklace chain be?

[BabCNesbitt]

Buying a necklace for myself online and it gives a choice of chain lengths: 16", 18", or 24". What's 'standard'? Does it depend on boob size? Was going to wear it to a wedding but don't have the dress to wear with it yet.

Thanks!

My favourite one is 20" I think, it depends on the width of your neck and how high up your boobs are and size wise imo.
Try it with pieces of string first?

Brilliant, hadn't thought of that!

That's a great idea. I think I go for 16 or 18 in, never the long ones as they'd settle between my boobs - not a good look!