Blank Development Calculator
Develop the correct flat blank dimensions for a formed part by accounting for bend allowances along the neutral axis.
Using this calculator responsibly
The Blank Development calculator is an engineering aid for checking a shop-floor estimate before a setup, quote, or process review. Enter values in the units shown, confirm material properties against the applicable specification, and keep a record of the assumptions used. Calculator output does not override machine capacity, tooling limits, part requirements, or a qualified engineer's approval.
Before using a result in production, repeat the calculation with the extreme values allowed by the print or process window. Check that the selected material, thickness, geometry, and safety factor reflect the actual job. If a result approaches a press, die, fastener, or machine limit, stop and verify it with the equipment manufacturer or responsible engineer.
Inputs and results
Read every field label before entering data and avoid mixing inch and metric values. A useful result should be traceable to the job number, revision, material certification, and machine or tooling record. Treat warnings, invalid ranges, and unusual outputs as reasons to inspect the inputs rather than as values to work around.
The flat blank for a formed part is the sum of the flat flange lengths plus the material consumed by every bend (the bend allowances along the neutral axis).
Get the bend allowances right — via K-factor or tested values — and the blank cuts to size the first time.
Formula: Blank length = Σ flat flange lengths + Σ bend allowances
Worked example
- Two 1.000 in flanges joined by a 90° bend with BA = 0.238 in.
- Blank length = 1.000 + 1.000 + 0.238 = 2.238 in.