Is bend allowance added to the flat blank?
Yes. Bend allowance represents material length through the bend arc and is included when calculating the developed flat length.
Sheet metal
Bend Allowance Calculator
Calculate the developed arc length of a bend using bend angle, inside radius, material thickness, and K-factor.
mild steel16 ga0.0598 in1.519 mm
Static reference
Common thickness, radius, and angle combinations
| Gauge | Thickness | Inside radius | Angle | Bend allowance | Bend deduction |
|---|---|---|---|---|---|
| 16 ga | 0.0598 in / 1.519 mm | 0.0598 in / 1.519 mm | 45 deg | 0.0667 in | 0.0324 in |
| 12 ga | 0.1046 in / 2.657 mm | 0.1569 in / 3.985 mm | 90 deg | 0.3155 in | 0.2075 in |
Interactive calculator
Bend Allowance Calculator
Bend allowance0.1334 in
Neutral axis radius0.0849 in
FAQ
Specific checks for this calculator
Why does inside radius change bend allowance?
A larger inside radius moves the neutral-axis arc over a longer path, increasing the bend allowance for the same angle and thickness.