Men's necklaces are worn at different lengths based not only on the style of the necklace - but on the statement you want to make. The same necklace worn short at your collar looks vastly different than worn extra long down the front of your shirt!
This image shows where necklaces fall around the average man's neck –
If possible, measure around your neck with a piece of string laying at the length you would like your necklace. You don't need to do any extra math(!) - necklace lengths already include the additional length added by the clasp. If you are buying a gift and don't know the recipient's neck size, the safest bet is to go with a 20" necklace. That is the most common length and has the most versatility for different shirt styles - and will give some leeway for men with larger necks. Of course, an adjustable necklace will always be a plus.
|18"||For adults, this length falls at the base of the neck. For larger men, this length may be too tight. For younger men, or men with smaller necks, this length will fit comfortably at the base of the neck. Generally, this length is not worn with pendants - although very small pendants or focal pieces in the middle of the necklace could work, depending on the style. Although the picture above shows this length necklace over the top of the t-shirt, in reality, a pendant on this length of necklace would flip between being over or under a round-collared shirt.|
|20"||The most common men's necklace length. It falls at the collarbone, somewhere between the 1st or 2nd button on a button-down shirt. This length is a good option for pendants, as the length will keep the pendant on top of round-collared shirts and show well for button shirts with the top two buttons open. This is also a good length for the average v-neck shirt. For men with larger necks, this is the smallest size I would advise unless you can measure neck size.|
|22"||This is also a very common men's necklace length. It looks good with a pendant. It will fall a couple of inches below the collarbone. It tends to be just under the 2nd button of a button-down shirt. This length can be worn over or under a shirt, depending on the style goal of the necklace.|
|24"||This length falls at the middle of the sternum. It tends to be worn over the shirt, although some men like to wear pendants such as dog tags under the shirt with this length chain. Either over or under a shirt, this is another common length for pendants, such as crosses, dog tags and other interesting pendants.|
|30"||The longest of a standard length men's necklace, this length is designed to be worn over the shirt. Typically, it's a plain chain with no pendant, but in some cases it can be designed with an interesting pendant.|
|36"||This is an unusual and non-standard men's necklace length. It's extra-long and falls far down the chest. Depending on your head and neck size, you may be able to wrap this and wear it as a double strand shorter necklace.|