Weld Fillet Size Calculator
Determine the code-required minimum and maximum fillet weld sizes for structural joints based on the thickness of the material being welded.
Enter Material Thickness
Provide the thickness of the plate to determine the allowable fillet weld size range.
The "Goldilocks" Weld: Not Too Small, Not Too Big
The size of a fillet weld is a critical design parameter. It must be large enough to be strong, but not so large that it wastes material or causes problems. Welding codes like AWS D1.1 provide specific rules for both the minimum and maximum allowable size of a fillet weld.
- Minimum Size: The minimum size is required to ensure that there is enough heat input to overcome the "quenching" effect of the base metal. A weld that is too small on a thick plate will cool too quickly, potentially leading to cracking. Therefore, thicker plates require a larger minimum weld size.
- Maximum Size: The maximum size is limited to prevent a weld from being so large that it overstresses the edge of the plate. For plates less than 6mm thick, the weld cannot be larger than the plate thickness. For plates 6mm or thicker, the weld must be at least 1.5mm smaller than the plate edge to avoid creating a sharp notch.