What is throat thickness?
Throat thickness is the minimum weld cross-section where force flows. A 3/16" fillet has throat of about 0.11"—less than the leg size.
Engineering
Weld Strength Calculator
Approximate the weld capacity in shear or tensile based on weld size and material properties.
Welding Joint Analysis
Simplify your fabrication checks with a quick weld strength estimate.
What this calculator does
The Weld Strength Calculator estimates load capacity of welded joints based on fillet weld geometry, material properties, and design standards. It helps engineers verify welds can safely carry intended loads and comply with codes like AWS guidelines.
How it works
The calculator computes effective throat thickness (throat = 0.707 × leg size), then multiplies by length and number of welds for total area. Capacity = area × material strength × efficiency. A safety factor of 2.0 is applied.
Formula
Throat = 0.707 × Leg Size. Weld Area = Throat × Length × Number. Weld Capacity = Area × Strength × Efficiency. Allowable Load = Capacity ÷ 2.0.
Tips for using this calculator
- Larger leg sizes increase capacity non-linearly due to area effects
- Weld efficiency (0.6-0.8) accounts for defects
- Multiple smaller welds are often stronger than one large weld
- Use shear strength unless weld is specifically tensile-oriented
- Verify applied load doesn't exceed allowable load
Frequently asked questions
When use shear vs tensile strength?
Use shear for typical fillet welds where load is parallel to weld. Use tensile when force is perpendicular. Most applications use shear.
What does weld efficiency mean?
Efficiency accounts for defects reducing capacity below theoretical values. Standard: 1.0 for X-ray inspected, 0.70 for assumed defects.