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

Bend Angle Degrees (°)

Required number input.

Inside Radius Millimeters (mm)

Required number input.

Thickness Millimeters (mm)

Required number input.

K Factor

Required number input.

Sheet-metal bend allowance from bend angle, inside radius, thickness and specified K-factor: BA=θ(R+Kt). 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]

Bend Allowance Millimeters (mm)

The resulting bend allowance millimeters returned as a number.

• Bend allowance and deduction depend on actual tooling, inside radius, thickness, material, grain direction, angle, springback, and the shop's K-factor or bend table. Test coupons are preferable when finished dimensions are critical.
• 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.

• Bend Deduction

  Sheet-metal bend deduction 2(R+t)tan(θ/2)−BA using an already calculated bend allowance.

• Cam Lift Simple Harmonic

  Simple-harmonic cam follower displacement over a specified rise angle, with zero at start and full lift at end.

• Column Slenderness Ratio

  Column slenderness KL/r from effective-length factor, unsupported length and radius of gyration.