Notch & Relief Calculator
Calculate corner relief dimensions for sheet metal bend clearance including round, rectangular, and slot relief types.
Inputs
mm
mm
°
Results
Recommended Relief Width
4.38 mm
Recommended Relief Depth4.2 mm
Round Relief Diameter7 mm
Minimum Relief Width3.5 mm
Bend Line Offset2.75 mm
Min Bend-to-Bend Spacing6 mm
Relief Area Removed38.48 mm²
How to Use This Calculator
- Enter material thickness, inside bend radius, and bend angle.
- Select relief type (round drilled hole, rectangular slot, or V-notch).
- Review relief size, minimum relief diameter, and relief position relative to the bend line.
- Relief cuts prevent tearing at bend ends -- always required when bending to the edge of a flange.
- Round relief holes reduce stress concentration better than rectangular slots for ductile materials.
How the result changes with Inside Bend Radius
| Inside Bend Radius | Recommended Relief Width |
|---|---|
| 5.09 | 8.24 mm |
| 18 | 24.38 mm |
| 33 | 43.13 mm |
| 45 | 58.13 mm |
What each input means
- Material Thickness
- Sheet metal thickness.
- Inside Bend Radius
- Inside radius of the bend at the corner.
- Bend Angle
- Bend angle in degrees.
- Relief Type
- Shape of the corner relief cut.
What each result means
- Round Relief Diameter
- Shown only for round relief type.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersMaterial Thickness = 1.5, Inside Bend Radius = 2, Bend Angle = 90, Relief Type = 1 = 4 input(s) provided
- Calculate Recommended Relief WidthRecommended Relief Width4.38 = 4.38
- Calculate Recommended Relief DepthRecommended Relief Depth4.2 = 4.2
- Calculate Round Relief DiameterRound Relief Diameter7 = 7
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Sheet Metal
Bend Allowance Calculator
Calculate flat pattern bend allowance and deduction from material thickness, bend angle, inside radius, and K-factor.
Sheet MetalHem & Seam Calculator
Calculate material allowance for various sheet metal hem and seam types including open, closed, teardrop, and rolled hems.
Sheet MetalK-Factor Calculator
Determine K-factor from material type, thickness, bend radius ratio, and bending method for accurate flat patterns.
More in Manufacturing, Industrial & Coatings.