Weld Strength Estimator
Quickly estimate the shear strength capacity of a fillet weld. This tool is for educational and estimation purposes only and should not be used for final engineering design.
Weld Parameters
Enter the weld dimensions and electrode type to get an approximate strength value.
How is Weld Strength Calculated?
The strength of a weld is its ability to resist an applied force. For fillet welds, the primary concern is usually shear strength—the force trying to slide one plate past the other. This calculator provides a simplified estimation based on a standard formula used in structural welding.
The Core Formula
The capacity of a fillet weld is determined by its effective area and the shear strength of the weld metal.
Force = Weld Area × Allowable Shear Stress
- Weld Area: This isn't just length times width. For a fillet weld, the critical area is the "effective throat," which is calculated as `0.707 × Weld Leg Size`. The total area is then `Effective Throat × Weld Length`.
- Allowable Shear Stress: This is a property of the welding electrode used. A common rule of thumb in weld design codes (like AISC) is that the allowable shear stress is 30% of the electrode's ultimate tensile strength (e.g., for an E70XX electrode with 70,000 psi tensile strength, the shear strength is ~21,000 psi).