Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Base Amperes (A)

Required number input.

Derating Factor

Required number input.

Adjusted current rating from a base ampacity times a supplied 0–1 derating factor; not a code sizing result. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Derated Amperes (A)

The resulting derated amperes returned as a number.

• Conductor ampacity and diameter selection depends on material, insulation rating, ambient temperature, bundling, installation method, terminals, voltage drop, fault current, harmonics, and applicable electrical code. A geometric conversion does not establish a safe circuit rating.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Cable Sizing Current Capacity

  Usable conductor current rating from a supplied base ampacity times installation and temperature derating factors; not a code sizing determination.

• Bolt Shear Capacity

  Nominal single-shear force from bolt shear area times a user-supplied allowable shear stress; not a code-rated connection capacity.

• Fracture Toughness Stress Intensity

  Mode-I stress-intensity factor KI=Yσ√(πa) for a supplied geometry factor; not a fracture or safety assessment.