At Lat & Lo™, the standard overall length for most of our coordinates necklaces is 18". We find that generally, this length works best for a variety of customers and designs.
However, we do offer some styles in a shorter or longer chain length. (Chain lengths are listed within the product description.) Though each customer's body type and/or preference will vary, for our male customers, we generally recommend a chain length of at least 20".
For your visual reference, this style chart has been provided.