The most commonly used thickness of tape can vary depending on the specific application and industry. However, for general-purpose packaging and sealing applications, the most commonly used thickness of tape is typically around 2 mil to 3 mil (0.002 to 0.003 inches) or 48 to 72 microns.

This thickness provides a good balance between strength, flexibility, and cost-effectiveness. It allows the tape to adhere well to surfaces, provide sufficient sealing strength, and resist tearing or breaking during handling and transportation.

However, it's important to note that different applications may require tapes of different thicknesses. For heavy-duty or industrial applications, thicker tapes with higher tensile strength may be preferred. Conversely, for lightweight or delicate items, thinner tapes may be used to minimize the risk of damage.

Additionally, specialized tapes, such as electrical tapes or medical tapes, may have specific thickness requirements based on their intended use and industry standards.

When choosing the appropriate tape thickness, it's recommended to consider factors such as the weight and nature of the items being sealed, the surface texture and condition, the desired level of adhesion, and any specific industry or application requirements. Consulting with tape manufacturers or suppliers can provide additional guidance in selecting the most suitable thickness for your specific needs.