Physics

Bend Allowance Calculator

Find the bend allowance for sheet metal forming.

Bend angle (°)

Inside radius

Material thickness

K-factor

Calculated Output

Bend allowance 9.236

Formula: BA = (θ·π/180)·(R + K·t)

Step-by-Step Breakdown

1. Values used:

2. Bend angle = 90 °

3. Inside radius = 5

4. Material thickness = 2

5. K-factor = 0.44

7. Bend allowance = 9.236

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The math behind it

BA = (θ in radians)·(R + K·t). The K-factor locates the neutral axis (typically 0.3–0.5).

90° bend, 5 mm radius, 2 mm thick, K 0.44 → about 9.24 mm.

Why does it matter?

It sets the flat blank length so the part bends to the right final size.