BendTab.Free tools. Clear working.
English

BEND ALLOWANCE & DEDUCTION

Know what happens in the bend.

Calculate BA, BD and outside setback using a K-factor or your measured bend data.

SINGLE-BEND WORKBENCH

01 / Define your bend

Initial values are a worked example, not material presets.

Use a decimal point or comma; do not use thousands separators.

mm
mm
Angle convention
°
Aθ

A = 90.0°θ = 90.0°A + θ = 180°

02 / Choose your basis

Keep measured values tied to the same material and process. No generic material presets are supplied.

THE GEOMETRY
TRA = 90°NEUTRAL AXIS

Cross-section schematic · not to scale

YOUR RESULT

Bend allowance

2.199mm
Bend deduction1.801 mm
Outside setback2.000 mm
Input K-factor0.4000

Calculated with your K-factor. Display is rounded; calculations retain precision.

One recent calculation per tool, on this browser only.

Formulas, sources & supported range ↗

BendTab calculation record

BendTab — Bend allowance and deduction
Model: bendtab-geometry-1.0.0
Method: K-factor
Thickness T: 1 mm
Inside radius R: 1 mm
Bend angle A: 90 deg (amount bent)
K-factor: 0.4 
Included angle θ: 90°
BA: 2.199115 mm
BD: 1.800885 mm
OSSB: 2.000000 mm
Effective K-factor: 0.400000
Source / process notes: Not supplied. Example values are not production presets.
BA = α × (R + K × T); OSSB = (R + T) × tan(α/2); BD = 2 × OSSB − BA
α is amount bent in radians. X and Y are outside mold-line dimensions.
Reference: https://help.autodesk.com/cloudhelp/2023/ENU/Inventor-Help/files/GUID-7B2525E4-8191-46F2-8CC3-FF422114EAE5.htm
Verify process inputs and drawing tolerances against a test bend.

BEFORE YOU USE THE NUMBER

Use the basis you actually have.

K-factor mode calculates the bend allowance from BA = α(R + KT). If you have a measured allowance or deduction for the same conditions, enter it directly. The tool preserves that input and derives the related values.

BA is added to tangent-to-edge straight lengths. BD is subtracted from the sum of correctly defined outside mold-line dimensions. The two paths describe the same part.

Open the L-profile calculator →