Sheet Metal K-Factor Calculator
Construction & Home ImprovementEstimate the sheet metal bending K-factor and neutral axis location from bend radius and material thickness.
Estimated K-Factor
Estimated ratio locating the neutral axis within the material thickness.
Neutral Axis Location
0.0198
Distance of the neutral axis from the inside surface of the bend.
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Odeh Ahwal0people find this calculator helpful
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Construction & Home Improvement calculators
Frequently Asked Questions
Is this simplified K-factor accurate enough for precision work?
No, this uses a commonly cited rough rule, a lower K-factor for a tight bend radius under about twice the material thickness, and a higher K-factor for a larger radius bend. There is no single standardized threshold across the industry for exactly where this transition happens. Real fabrication shops determine K-factor empirically per material grade, thickness, tooling, and bend method, using material and tooling specific charts or physical test bends.
What is a K-factor used for?
K-factor describes where the neutral axis, the layer of material that neither stretches nor compresses during a bend, sits within the material thickness. It is used to calculate bend allowance and flat pattern length for sheet metal parts.
Why does a tighter bend radius have a lower K-factor?
A tighter bend compresses the inside material more severely relative to the outside, pushing the neutral axis closer to the inside surface. A larger radius bend behaves more like simple beam bending, with the neutral axis closer to the true center of the material.
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