How to use the coaxial cable capacitance calculator
Find the capacitance per cable length of a coaxial cable from its radii and insulator. Enter cable length, inner conductor radius, outer conductor radius, dielectric constant in the fields above; the capacitance is computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “coax capacitance”, “cable capacitance”, “coaxial cable pF”, “calculate coaxial cable capacitance”, “find capacitance”.
Formula
Variables
- L — Cable length (m)
- a — Inner conductor radius (mm)
- b — Outer conductor radius (mm)
- er — Dielectric constant
Worked example
With cable length = 10 m, inner conductor radius = 0.5 mm, outer conductor radius = 2 mm, dielectric constant = 2.3, the calculator gives capacitance ≈ 922.9985 pF.
Frequently asked questions
What is the coaxial cable capacitance calculator used for?
Find the capacitance per cable length of a coaxial cable from its radii and insulator. It helps with questions such as “coax capacitance”, “cable capacitance”, “coaxial cable pF”.
What is the formula for the coaxial cable capacitance calculation?
Capacitance (pF) = 2 × π × EPS0 × er × L / ln(b / a) × 1e12. Here L is cable length (m), a is inner conductor radius (mm), b is outer conductor radius (mm), er is dielectric constant.
What inputs do I need for the coaxial cable capacitance calculator?
You need cable length in m, inner conductor radius in mm, outer conductor radius in mm, dielectric constant. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the coaxial cable capacitance calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the coaxial cable capacitance result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.