Pacific Roll LLC
Arc Length Calculator
Enter your radius (inside, outside, or centerline), material depth, and any two of angle, arc, or chord — all values solve instantly.
Units (length)
Step 1 — Material
Choose which radius you know, enter it along with the material depth.
I know the...
Measured to the outer face of the member
Dimension in the plane of the bend (e.g. 12 for a 12x12 tube)
Step 2 — Bend geometry
Enter any two values — the third calculates automatically.
Total included angle (degrees)
Arc length along the outside face
Straight-line end-to-end distance
How to Use
- 1.
Select your unit of measurement.
- 2.
Choose which radius you know — outside, centerline, or inside.
- 3.
Enter that radius value and the material depth (the dimension in the plane of the bend — 12 for a 12x12 tube, the d-dimension for a wide-flange).
- 4.
The calculator derives all three radii immediately.
- 5.
Type any two of: bend angle, outside arc, or chord length.
- 6.
All remaining values solve instantly. Use Print / Save PDF to export a results sheet.
Definitions
Outside Radius
Distance from the center of curvature to the outer face of the member.
Centerline Radius
Distance to the neutral axis — outside radius minus half the depth. Used for all arc calculations.
Inside Radius
Distance to the inner face — outside radius minus the full depth.
Material Depth
The dimension of the member in the plane of the bend — 12 for a 12x12 tube, the d-dimension for a wide-flange.
Bend Angle
Total included angle swept by the bend. A quarter-circle is 90 deg; a half-circle is 180 deg.
Outside Arc
Arc length along the outer face — the longest arc, often used for material ordering.
Centerline Arc
Arc length along the neutral axis of the member.
Inside Arc
Arc length along the inner face — the shortest arc.
Chord Length
Straight-line distance between the two endpoints of the bend.
All arc calculations use the centerline radius. For tight bends, consult our team — springback and section distortion may affect final dimensions.