K Factor Calculator
Estimate sheet-metal bend K factor from bend allowance, inside radius, material thickness and bend angle before fabrication planning.
Technical Calculator
K Factor Calculator
Calculate an indicative K factor for stainless steel sheet and plate bending, then confirm tooling, springback and material behavior with the fabricator.
Sheet Metal K Factor
Enter bend allowance, inside radius, thickness and bend angle for one bend.
Use the same angle and bend allowance convention as the approved drawing or bend table.
Calculation Result
This is an indicative geometric estimate. Confirm tooling, springback, grain direction, temper and shop-specific bend data.
- Bend allowance calculation
- Neutral axis offset
- Downloadable calculation result
Technical Reference
K Factor Basis and Limits
K factor locates the neutral axis through the material thickness during a bend. It is derived from bend allowance, inside radius, thickness and included bend angle.
This estimate assumes the bend allowance and angle refer to the same bend definition. Shop conventions can differ for inside angle, outside angle and bend deduction.
A calculated value outside the usual 0 to 1 range should be reviewed instead of silently accepted. Tooling, springback, grain direction and alloy condition can change the practical result.
Use the calculator for early planning, then validate the final bend table or test coupon with the fabricator.
Calculation Method
Formula and Worked Example
K Factor Formula
Derive the neutral-axis position from bend allowance, included angle, inside radius and material thickness.
Worked Example
With 7.85 mm bend allowance, 90° angle, 3 mm inside radius and 2 mm thickness, the indicative K factor is approximately 1.00.
Quotation Planning
How to Use This Estimate in a Quote
Include bend allowance, inside radius, thickness and angle when sharing the estimate.
State whether the angle is the included angle or the bend rotation used by the shop.
Ask the fabricator to confirm springback, tooling and bend deduction before release.
Review Limits
What Can Change the Result
- K factor can vary by alloy and temper.
- Inside radius and angle conventions must be explicit.
- A calculator result is not a tooling approval.
- Keep the approved bend table with the drawing.
Request for Quotation
Send Your K Factor Calculator Requirement
Send the K factor estimate with material grade, thickness, bend radius, angle, quantity, finish and fabrication requirements.
- Grade and material condition
- Thickness, radius and angle
- Bend allowance or deduction
- Quantity and finished dimensions
- Tooling, finish and destination
Frequently Asked Questions