Sheet Metal Bend Calculator

Sheet Metal Bend Calculator helps fabricators, HVAC shops, and press-brake operators get bend allowance, bend deduction, and flat pattern length right before cutting - so the finished part lands on its actual dimensions instead of coming up short or long after every bend.

Enter material thickness, bend angle, inside radius, and K-factor to get bend allowance, bend deduction, outside setback, and neutral axis radius. Chain multiple bends together to solve a full flat pattern, or reverse-solve K-factor from a real test bend on your own tooling.

BEND ALLOWANCE
- Bend angle is measured bent from flat (0 degrees = flat stock, 90 degrees = right-angle bracket), matching how a press brake operator reads a protractor against the material
- K-factor chips for soft aluminum, steel, and stainless steel, or enter your own
- Results: bend allowance, bend deduction, outside setback, and neutral axis radius
- Inch or millimeter input

FLAT PATTERN
- 2 to 5 flange lengths with a per-bend angle and radius for each bend between them
- Total flat length and a per-bend breakdown table
- Copy the breakdown to the clipboard or export it as text to share

K-FACTOR FINDER
- Enter a test bend's thickness, radius, angle, and flange lengths, plus the flat length you actually measured before bending
- Get back the K-factor implied by that real bend, so future jobs on the same material and tooling use a number pulled from your own shop instead of a textbook default

GAUGE TABLES
- Gauge-to-thickness reference for mild steel, galvanized steel, stainless steel, and aluminum, gauges 3 through 30
- Inches and millimeters side by side

This app works fully offline - no data connection needed to run a calculation.

Bend allowance and bend deduction formulas use standard K-factor theory. Actual results can vary with material lot, tooling, and press brake setup - confirm critical dimensions with a test bend before committing to a production run.

This app is ad-supported. Exporting a flat pattern may show a short video ad; if no ad is available the export still happens.