Sizing a hammock will come down to two dimensions: width and length. Width has been fairly standardized into ‘single’ and ‘double’ occupant designations, with single hammocks being around 5 feet in width, and double hammocks being around 6. A single hammock will save some weight and bulk over a double hammock, while a double will be more useful for hanging out in camp.
The length of your hammock will play a bigger role for those who are looking to sleep in their hammocks, with the range falling between 7 and 11 feet. For most people, a 9-10 foot long hammock will suit all of their needs. Closely related to the length of your hammock will be the ridgeline length, which is a structural cord that runs between the ends of your hammock, and suspends the fabric at the correct angle.
When it comes to tuning in your ridgeline length, the consensus is to go with around 5/6, or 83%, of your hammock length.