What size nails should be used for framing?

The framing process relies primarily upon lumber that is two inches deep, and the nails best suited for this size of board are between 2.5 inches and 3.5 inches long. In the United States, these will be identified using the penny system rather than by the length of the nails directly. The penny system is represented by a number followed by the letter "d." This is a somewhat archaic method of identification, but it is still used in the United States despite it making little sense in the contemporary world. The "d" is used because of the Roman penny, which was called "denarius." Most people in the world have moved on to other methods of identifying hardware, but the United States has stuck with the penny system in the same way that it has stuck with the imperial system of measurement, despite the example set by most of the world.

For example, a nail labeled as "16d" is 3.5 inches long. A 10d framing nail is 3 inches long, and an 8d framing nail is 2.5 inches in length. These three sizes of common nail are the most important for framers. Which size you use will depend on the exact nature of the point that you are fastening.