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TaskJunction Calculator

Weld Joint Strength Calculator

Free weld joint strength calculator for fillet and butt welds. Check weld stress under axial, shear and bending loads. Calculates safety factor and pass or fail status.

🔗 Weld Parameters
For fillet welds: leg size. Throat = 0.707 x leg size
Force in N, or Moment in N.mm for bending
Typically 0.4 x Sut for fillet welds (IS 816)
📊 Results
Actual Stress
--
MPa
Allowable Stress
--
MPa
Throat Area
--
mm²
Safety Factor
--
FOS
Calculate to see result
Reference Formulas
Fillet Weld Throat
t = 0.707 x s (for 45 degree fillet)
s = weld leg size. Throat is the minimum cross-section
Shear Stress (Axial)
tau = P / (t x L)
P = applied force, t = throat, L = weld length
Bending Stress
sigma = M x y / I_weld
For line weld: I_unit = L^3/12. Then multiply by t
Safety Factor
FOS = tau_allowable / tau_actual
FOS greater than 1 means weld passes the check
From the builder
Why I built this

I kept having to calculate weld joint strength checks in my work, comparing fillet welds to butt welds, checking if a weld would handle the load with a sensible factor of safety. The typical approach is to use Shigley's or IS 816 tables but translating those into a quick check for a specific geometry always took more time than it should.

This calculator handles fillet and butt welds under axial, shear and bending loads. It flags the safety factor and tells you directly whether the weld passes. I set FOS 2.0 as the threshold for a clear safe result, which is the common design practice, but you should always verify against your specific material and code requirements.

Vaibhav Dhokpande, Creator of TaskJunction