Not sure which size to buy or use? The general rule is the higher the number, the finer and shorter the needle.
Use Sharps size 2, 3 and 4 for general sewing on medium to heavy fabrics. Sharps in size 5, 6, 7, 8, and 9 are the most popular within the sharp's range and they are commonly used for general sewing on light to medium fabrics.
Sharps size 10, 11 and 12 these needles are ideal for creating small delicate stitches and are quick and easy to use.
