Calculator
Formula Used
Average shear stress is computed as: τ = F / (A × n) where F is force, A is the resisting shear area, and n is the number of shear planes.
- 1 Pa = 1 N/m²
- kPa and MPa are scaled Pascals; psi is pounds per square inch.
- If you enter allowable stress and factor of safety, the calculator reports utilization and an actual safety factor.
How to Use This Calculator
- Select a calculation mode: shear stress, required area, or allowable force.
- Enter force and/or area as required by the selected mode.
- Set the number of shear planes for single or double shear.
- Optionally add allowable stress and factor of safety for design checks.
- Press Calculate to show results above the form, then download CSV or PDF if needed.
Example Data Table
| Case | Force (N) | Area (mm²) | Planes (n) | Shear Stress (MPa) | Notes |
|---|---|---|---|---|---|
| A | 1200 | 300 | 1 | 4.00 | Single shear pin |
| B | 1200 | 300 | 2 | 2.00 | Double shear joint |
| C | 5000 | 450 | 1 | 11.11 | Higher load on small area |
| D | 800 | 1200 | 2 | 0.33 | Large area reduces stress |
Tip: 1 mm² = 1×10⁻⁶ m², so MPa matches N/mm² numerically.
Export Options
After a calculation, use the buttons in the result box to download a CSV summary or a compact PDF report of your inputs and outputs.
What Shear Stress Represents
Shear stress (τ) is the average tangential stress that resists sliding between adjacent layers of a material. In this calculator, τ is computed from applied force, resisting area, and the number of shear planes. This is widely used for pins, bolts, rivets, lap joints, adhesive bonds, and thin webs where the dominant failure mode is shear. In many steel joint checks, working shear stresses often fall in the tens to low hundreds of MPa, while polymers and woods can be far lower. Treat your material data sheet or code allowables as the governing input.
Units and Conversions You Can Audit
The base unit is the Pascal, where 1 Pa equals 1 N/m². Engineering work typically uses kPa and MPa to keep numbers readable, while psi is common in US customary workflows. A practical cross-check is N/mm²: 1 MPa equals 1 N/mm² numerically, which helps validate results when your geometry is entered in mm² and reduces unit-entry mistakes significantly.
Single vs Double Shear Changes the Result
The shear-plane input (n) captures whether a connector is loaded in single shear (one resisting plane) or double shear (two planes). For the same force and area, doubling n halves the average shear stress. This matters in clevis connections and forked brackets, where load sharing across multiple planes can substantially reduce stress and improve joint efficiency.
Design Checks with Allowables and Safety Factor
If you enter an allowable shear stress, the calculator reports utilization as τ divided by the design limit. When a factor of safety is provided, the design limit becomes allowable ÷ factor of safety, aligning with conservative sizing practice. The reported “actual safety factor” is the inverse of utilization, giving a quick margin-of-safety indicator for screening alternatives.
Typical Data Issues and How to Avoid Them
The most common input error is area mismatch: using the gross cross-section instead of the net shear area at the critical plane. For pins and bolts, confirm whether the shear plane passes through the shank or threaded portion, since the effective area differs. Also confirm unit intent (mm² vs cm²), and treat “average shear” as a first-pass estimate; real joints can have stress concentrations and nonuniform distributions.
FAQs
It uses average shear stress: τ = F ÷ (A × n), where F is force, A is resisting shear area, and n is the number of shear planes.
Use n = 2 for common double-shear joints, such as a pin in a clevis where the load is shared across two parallel shear planes.
Pa is the base unit for consistency, while MPa or kPa keeps values readable. Many designs also use MPa because 1 MPa equals 1 N/mm².
Utilization is τ divided by the design limit. If you also enter a safety factor, the design limit becomes allowable stress ÷ safety factor.
Yes. Choose “Compute required area,” enter force, target stress, and shear planes. The output is the minimum resisting area needed to meet that stress.
It is an average-stress estimate. Real connections may have stress concentrations, bending, frictional effects, or uneven load sharing, so verify with standards, test data, or detailed analysis for final designs before you finalize dimensions safely.