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Cable Bend Radius Calculator 

Calculate the minimum bend radius for cables and wire harnesses using IPC/WHMA-A-620, NASA, or custom engineering requirements.

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Input Parameters

Use optimum as the preferred design target where space allows. Treat minimum as the lower limit.

IPC bend radius values are class-based minimums.

Enter multiplier as OD factor, e.g. 10 for 10 x OD.

Results

Minimum Bend Radius

80 mm

3.15 in

10 x Cable Diameter

Source
IPC/WHMA-A-620
Type
Flexible coaxial cable
Requirement
Class 1
Cable bend radius is measured toward the inside curve Cable OD = 8 mm R = 80 mm Measured toward inside Target radius Minimum limit Note: OD = outside diameter
Wider At or Above Target Tighter
Preview bend: 80 mm

Calculation Reference

  • Bend Radius = Cable Outer Diameter x Multiplier
  • NASA values can be optimum targets or minimum limits.
  • IPC/WHMA-A-620 values are minimum requirements by product class.

IPC/WHMA-A-620 values are class-based minimum bend radius requirements. Use the cable manufacturer specification where required.

Quick Reference

Flexible coaxial cable 10x OD minimum
Fixed coaxial cable 5x OD minimum
Ethernet cable 4x OD minimum
OD = outside diameter

This calculator provides engineering guidance only. For critical applications, verify against the governing standard, manufacturer datasheet, drawing notes, and program-specific requirements.

quick guide

How to use the Cable Bend Radius Calculator

Four steps to get a minimum bend radius for your cable design.

1. Enter the cable’s outer diameter (OD) in mm or inches.

2. Pick a multiplier source: IPC/WHMA-A-620, NASA, or Custom.

3. Choose the cable type and your standard’s options.

4. Get results for the minimum bend radius in mm and inches.

Where do I find the cable diameter (OD)?

If you’re designing in the Pickering Cable Design Tool, the overall diameter is shown for every path. Select a segment and read the value in the Product Details tab in the right panel, for example Segment S1 (Ø ≈12.2 mm), as shown below.

The Cable Design Tool shows each segment’s approximate diameter in the Product Details panel.

Bend Radius Calculation example

In this example, the Cable Design Tool gives the cable an overall diameter of 12.2 mm, and in this case it’s a 50-core screened (shielded) cable.

Since it’s a shielded cable and we want to build the cable according to IPC Class 3, we set the source to IPC/WHMA-A-620 and the cable type to Shielded wire & cable. Under IPC, that type has a defined minimum at Class 3, which sets the multiplier to 5 × the outer diameter. The calculator simply multiplies the two:

12.2 mm × 5 = 61 mm

Minimum bend radius: 61 mm. This is the tightest radius you should bend this cable to, measured to the inside of the curve.

The diameter from the tool is approximate. It’s the calculated cross-section of the cores and doesn’t include the screening or any outer sleeving, which usually add around 1 mm. For a real build it’s safer to add that first: 13.2 mm × 5 ≈ 66 mm.

For more on bend radius and how to measure, calculate, and apply it, you can read our article here.