Unbend: Sheet Metal Bend Calc

Unbend turns sheet metal dimensions into a cut ready flat pattern. Enter the shape, the thickness, the angle and the inside radius, and you get the blank length, the bend allowance, the bend deduction and a drawn pattern you can export to your cutter or print at true size.

Made for fabricators, ducting and HVAC shops, welders, coachbuilders and anyone who has to mark out metal before it goes to the brake or the plasma table.

SHAPES

Single bend at any angle
Multi bend profile, chained folds in one blank
U channel with two parallel legs
Z profile, offset step with opposite folds
Hem, an edge folded back on itself
Joggle, a small offset for a lap joint
Cone
Truncated cone
Cylinder and straight round duct
Truncated cylinder, cut at an angle
Segmented elbow, a gored bend developed from flat gores

BEND MATH THAT MATCHES THE PRESS

Bend allowance and bend deduction from published K-factor charts
K-factor resolved from the material, the thickness and the inside radius
Air bending, bottoming and coining
Mild steel, galvanized steel, stainless steel, aluminum and copper
Your own K-factor per material when you want the numbers to match your own tooling

FLAT PATTERN AND ORDINATES

Every pattern is drawn to scale, solid lines for cuts and dashed lines for bends
Station lines on rolled and curved developments
Ordinate table with X across and Y up from the bottom left corner of the pattern, so a pattern can be marked out with nothing but a tape measure
Pinch to zoom and fit to screen on the pattern view

EXPORT

DXF for CNC, plasma and laser cutting
PDF at 1:1 scale, print it, lay it on the sheet and mark straight through
PDF tiled across A4 or Letter with alignment marks, for patterns larger than one page
A calibration ruler on the first printed page, so you can prove the template came out true to size
Ordinates as CSV for a spreadsheet
Share the pattern as an image

UNITS

Millimeters or inches, switched in one tap
Inch fractions at the precision you actually work in
Results, ordinates and printed templates all follow the unit you chose

BUILT FOR THE SHOP FLOOR

Everything is calculated on the device, so it works in a workshop with no signal
No account and no sign in
Save a job and reopen it later with every dimension still in place
Light and dark theme
Available in 15 languages

UNBEND PRO

One payment. There is no subscription and nothing renews.

Pro adds DXF export, 1:1 and tiled PDF templates, unlimited saved jobs and your own K-factor table. The unlock stays with your Google account, so it follows you to a new phone.

The free version calculates every shape, draws every flat pattern, shows the ordinate table and lets you save jobs.

Unbend does not replace your CAD seat. It is the tool for the moment you are standing at the bench with a tape measure and a piece of sheet, and you need the flat size before you cut.