Bend Allowance & Flat Pattern

Work through sheet-metal bend geometry with the measurements and assumptions you choose. Enter a bend angle, inside radius, material thickness, and K-factor to see bend allowance, setback, and bend deduction together. Switch between millimetres and inches while keeping the physical values consistent.

The app explains its formulas and angle convention in plain sight. A simple diagram illustrates a 90° cross-section; numeric calculations always use the angle you entered. These are starting geometry values, not material recommendations or fabrication-certified results. Verify them with a physical bend and your own shop practice.

Free single-bend calculation stays available without an account or internet connection. Optional Lifetime Pro is a one-time Google Play purchase, not a subscription. It adds multi-bend flat-pattern calculations using outside-mold-line segments, saved local scenarios, user-entered material/tooling notes, observed-versus-calculated allowance comparison, and JSON/CSV file export. Purchase availability and local price are supplied by Google Play.

Saved scenarios stay on your device. With Lifetime Pro, you can search them, reopen them, delete them, and create or import a JSON backup through Android's file picker. CSV worksheet export is also a Pro feature. A file saved to a provider or cloud location you choose is handled by that destination.

PatchMedia · contact@patch-media.com

Recent changes:
First release: single-bend allowance, setback, deduction, and optional flat preview. Lifetime Pro adds saved local scenarios and chained flat patterns.