# Bend Allowance

Written by Jerry Ratzlaff on . Posted in Structural Engineering

Bend allowance, abbreviated as BA, is the length of the arc through the bend area at the neutral axis.

## Bend Allowance formula

$$\large{ BA = \frac{\theta \; \pi}{180} \; \left( r \;+\; K \; t \right) }$$
Symbol English Metric
$$\large{ BA }$$ = bend allowance $$\large{in}$$ $$\large{mm}$$
$$\large{ \theta }$$ (Greek symbol theta) = bend angle  $$\large{deg}$$ $$\large{rad}$$
$$\large{ r }$$ = inside radius $$\large{in}$$ $$\large{mm}$$
$$\large{ K }$$ = K-factor $$\large{dimensionless}$$
$$\large{ t }$$ = material thickness $$\large{in}$$  $$\large{mm}$$