Welding Calculator
Calculate weld joint strength for fillet and butt welds with precision
Weld Strength Analysis
Single weld line perpendicular to load direction
Weld Properties
Length of the weld joint
Fillet weld size (leg length)
Material Properties
Maximum allowable tensile stress
Weld Strength Analysis
⚠️ Welding Safety Warning
• This calculator provides estimates for typical welding applications
• Always follow AWS D1.1 structural welding codes and standards
• Use qualified welders and proper welding procedures (WPS)
• Consider dynamic loads, fatigue, and environmental factors
• Perform non-destructive testing (NDT) for critical welds
• Consult structural engineers for load-bearing applications
Example Calculation: Single Transverse Fillet Weld
Weld Specifications
Weld Type: Single transverse fillet weld
Plate Thickness: 5mm
Weld Length: 100mm
Fillet Size: 5mm (equal to plate thickness)
Material: Structural steel with σt = 70 MPa
Weld Strength Calculation
• Formula: P = 0.707 × s × σt × l
• Weld size (s) = 5mm
• Tensile stress (σt) = 70 MPa
• Weld length (l) = 100mm
• Calculation: P = 0.707 × 5 × 70 × 100
• Throat thickness = 0.707 × 5 = 3.535mm
Result: P = 24,745 N = 24.745 kN
Weld Joint Types
Fillet Welds
Perpendicular plates, triangular cross-section
Butt Welds
End-to-end joints, full penetration
Lap Joints
Overlapping plates with edge welds
T-Joints
Perpendicular arrangement
Typical Stress Values
Structural Steel (MPa)
Welding Standards
Understanding Weld Strength Calculations
Fillet Weld Fundamentals
Fillet welds are the most common type of weld joint, used when plates are positioned perpendicularly. The strength depends on the throat area, which is the effective cross-sectional area that resists the applied loads.
Key Formulas
Single Fillet: P = 0.707 × s × σt × l
Double Fillet: P = 2 × 0.707 × s × σt × l
Butt Weld: P = t × l × σt
- P: Weld strength (N)
- s: Fillet weld size (mm)
- t: Throat thickness (mm)
- l: Weld length (mm)
- σt: Tensile stress (MPa)
- 0.707: Throat area factor for 45° fillet
Weld Design Considerations
Throat Thickness
For equal leg fillet welds, throat thickness = 0.707 × leg size. This is the shortest distance from root to face of the weld.
Load Direction
Transverse welds (perpendicular to load) use tensile stress. Parallel welds (along load direction) use shear stress.
Safety Factors
Apply appropriate safety factors based on load type, welding quality, and criticality of the joint.
Quality Considerations
- •Proper weld profile and penetration
- •Freedom from defects (cracks, porosity, undercut)
- •Correct electrode selection and parameters
- •Post-weld inspection and testing