When you need to replace screws or need more of the same kind, it is important that you use a screw size chart to ensure that you get the correct size. This will help to ensure that the screw will fit correctly, allowing it to be tightened or pulled out of the wood without any problems. Using a screw gauge or caliper to measure the screw is a good way to determine its size, but there are also many charts available that can help you as well.
The first number on a screw size chart is the major diameter of the threads, and the second number is the pitch, or the distance between each thread. For example, a screw with a size of 12” x 32 has a major diameter of 1/2 inch and a pitch of 32 threads per inch. If you don’t know how to read a screw size, you can always ask a hardware store employee for help.
In addition to the standard imperial screw sizes, most screw manufacturers now produce metric sizes as well. These are usually indicated on the packaging with a number preceded by the letter M, for example, M6 x 1. Metric screw sizes are designated according to strict international standards that ensure cross-compatibility of mating components. Generally, coarse (UNC) and fine (UNF) threads are provided for both imperial and metric screw sizes. For the most common metric sizes, our handy chart below provides a conversion table for determining their equivalent imperial sizes. screw size chart