Here is a general guide to chain lengths, for when you want to buy a necklace online, whether to yourself or as a gift. How long you want your chain to be is of course a personal choice, but it usually depends on the type of neckline the top you wear tend to have, so when buying a necklace as a gift you can use the same criteria. Does the person usually wear a round, turtle,boat or V-neck? Or does he/she mainly wear shirts? If so, is it worn buttoned up or unbuttoned?
You want you necklace/pendant to sit either on top of your clothes, or on bare skin, but not skimming the edge of the neckline, where the pendant will constantly disappear behind the edge of the top
Here are some examples:
Mini Heart 18ct Gold Pendant Necklacce on an approx 41 cm long chain
Nebula Pendant Necklace With Opal Triplet on an approx 46 cm long chain
Silver Knot Pendant Necklace on an approx 50 cm long chain
Long Demon Silver Necklace with a total length of approx 90 cm