Verbatim from Camping Survival
For those of you who have no idea what paracord is (and I didn't up until a year or two ago), it's like the duct tape of the fiber world. Paracord is nylon rope that was originally used in parachutes in World War II, which is where the name came from (originally it was parachute cord). Now it is a versatile utility cording that is still used extensively in the military, but is also gaining in popularity for personal use. Military-grade paracord is so useful that it deserves a Spin so those without military connections can learn about and make use of this great material.
Military-grade paracrod comes in six different types. We're going to focus on the best quality one that is most readily available to civilians: a variation of the military Type III paracord frequently called Mil-spec 550 paracord. Construction of 550 paracord is done by taking seven two-ply threads of nylon and wrapping them in a shell braided from 32 nylon strands. This composite construction gives paracord a tensile strength of 550 pounds (the outer sheath with the seven internal threads removed has a tensile strength of 200 pounds). Not only that, but paracord is mildew and rot resistant, and it's only 1/8" thick, making it great for a variety of uses. Here are some examples of the uses of paracord, many of which focus on its use as a tool to help you survive if you get lost hiking, or otherwise find yourself in a survival situation:
1) Bracelets, belts, and lanyards: Braiding objects with paracord that you have on you all the time is a great way to keep a little safety around your waist or wrist. If needed, say to tie down a load on the roof of your car, all you need to do is unweave the bracelet and voila! You are ready for the task at hand! This is especially useful for camping and hiking, where you can wear some safety on you so it doesn't take up room in your pack.
2) Dog collars and leashes: You can braid great custom dog leashes and collars out of paracord; paracord's strength and rot-resistance make it ideal for this purpose.
3) A saw: That's right! By pulling on a length of paracord fast enough to create actionable friction, you can saw some things in half, such as two-inch wide tubular webbing! Check out this brief video from Estela Wilderness Education, LLC for a demonstration.
4) Catching food: Paracord is so versatile it can be used to catch animal food, big or small. You can cut a length of paracord and remove one of the internal two-ply threads for use as fishing line, or use the in-tact cord for animal snares and traps.
5) Useful thread: The internal threads are also thin enough to sew on loose buttons or torn seams in clothing or tents, and even as dental floss.
6) Camp construction and utility: In any sort of camping situation (intended or not) paracord has too many uses to mention. Because of its strength and rot resistance, it can be used for things like pole lashing, pulling logs, hoisting food into trees for protection, and for guy strings and shelter ridge lines for tents or temporary shelters.
7) Making fire: Since paracord itself is nylon it won't burn for you but it does catch heat so it can be used as tinder to light larger pieces of kindling. And, you can use paracord as the necessary string in a bow-drill, a very basic and primitive way to make fire if needed. Here's information on making and using a bow drill from Nature Skills.
8) Medical emergencies: In the unfortunate instance that you get hurt while camping or hiking, paracord can literally save your life or the life of a friend. It can be used as a tourniquet, a sling, or to lash splints together on a broken limb. You can even string the paracord between two sapling trunks to make a stretcher of sorts.
9) Automobile fix: No, really! You can take 550 paracord and use it as a temporary replacement for something like a fan belt. Just be sure to knot the cord every few inches, otherwise the slippery nature of the cord will cause it to slip off.
10) Rappelling: No, paracord is not great as a regular climbing rope, but in an emergency situation you can rappel or otherwise haul your body weight with 550 paracord (provided you don't weight more than 550 pounds).
11) Woven items: With enough skill you can weave things from paracord such as water bottle holders, fishing nets, bird nets, or other traps.
12) Pulley systems: Around the house or in the woods, having a good block and tackle pulley system can allow you to haul and lift weights much heavier than you could without pulley assistance; paracord is great in pulleys.
13) Weaving rope: If paracord isn't strong enough for you, you can use it to braid even stronger rope for hauling or pulley purposes, such as to remove a stuck vehicle. This is an option if you are in a situation where you don't have proper rope available.