Cable Bend Radius Calculator

Respecting a cable's minimum bend radius is crucial for maintaining its performance and structural integrity. Bending a cable too tightly can cause irreversible damage, leading to signal loss, data corruption, or even complete failure. This calculator helps you determine the minimum safe bending radius for any type of cable, ensuring a reliable and long-lasting installation.

Calculate Minimum Bend Radius

Millimeters (mm) Inches (in)

function calculateBendRadius() { var diameterInput = document.getElementById("cableOuterDiameter"); var multiplierInput = document.getElementById("bendRadiusMultiplier"); var unitsSelect = document.getElementById("units"); var resultDiv = document.getElementById("result"); var diameter = parseFloat(diameterInput.value); var multiplier = parseFloat(multiplierInput.value); var units = unitsSelect.value; if (isNaN(diameter) || diameter <= 0 || isNaN(multiplier) || multiplier <= 0) { resultDiv.innerHTML = "Please enter valid, positive numbers for all fields."; return; } var minBendRadius = diameter * multiplier; resultDiv.innerHTML = "Minimum Bend Radius: " + minBendRadius.toFixed(2) + " " + units; }

Understanding the Calculation

The formula for calculating the minimum bend radius is straightforward and relies on two key pieces of information:

• Cable Outer Diameter (OD): This is the full thickness of the cable, including its jacket. You can usually find this on the cable's specification sheet or measure it with calipers.
• Bend Radius Multiplier: This is a factor determined by the cable manufacturer and is based on the cable's type and construction. It is typically expressed as a multiple of the cable's outer diameter (e.g., 4x, 10x). Always consult the manufacturer's datasheet for the most accurate multiplier.

Minimum Bend Radius = Cable Outer Diameter × Bend Radius Multiplier

Example Calculation

Let's say you are installing a Category 6A (Cat 6A) Ethernet cable with an outer diameter of 7.5 mm. The manufacturer's specification sheet states the minimum bend radius multiplier is 4x the outer diameter.

Using the formula:
7.5 mm (Outer Diameter) × 4 (Multiplier) = 30 mm
This means the cable should not be bent in a circle with a radius smaller than 30 mm.

Common Bend Radius Multipliers

While you should always check the manufacturer's specifications, the table below provides some common industry-standard multipliers for various cable types. These values typically apply when the cable is under tension (during installation) and may be lower for a fixed, static installation.

Cable Type	Typical Multiplier (Under Tension)	Typical Multiplier (Fixed)
Fiber Optic (Inside Plant)	20x OD	10x OD
UTP/STP (e.g., Cat 5e, 6, 6A)	8x OD	4x OD
Coaxial Cable (e.g., RG6)	10x OD	5x OD
Multi-conductor Power Cable (<600V)	8x OD	5x OD

Disclaimer: The values in this table are for general guidance only. Always refer to the specific cable manufacturer's datasheet for authoritative figures.