How to Determine What Size Screw You Have

Screws and a screwdriver.
What You'll Need
Nails & screws sizing chart

A sizing chart can help you determine if the screw size you have is appropriate for fastening certain objects. Manufacturers of these items supply the market with various types and sizes to suit buyers' needs.

Step 1 - Screw Length Identifier

The word “penny” is used as an identifier for screw length. Commonly used “penny” designations are 2d, 3d, 4d, 2-penny, 3-penny, and screws can be as long as 60-penny.

Step 2 - Types of Screws

The screw length is measured from the end of the nail until the head area in millimeters. The types of screws are oval-head, which is oval-shaped and protrudes in a semi-circle and the flat-head screw, which displays a level surface and is the easiest to measure. A ruler or a tape measure can be used to measure the length of the screw.

Step 3 - Determine the Diameter

To determine the diameter of the screw, measure in millimeters the head of the screw. The range of the screw sizes is from a small size (121/2) to a large size (2). The larger the diameter, the smaller the screw.