Please enter all required numeric values.
RESULTS
Input Parameters Specification
Wire Diameter dDiameter of the round wire above the reference plane.
Height hDistance from the plane to the wire center/position.
Length lLength of wire running above the plane.
Relative PermeabilityUse 1 for air or normal non-magnetic material.
Practical Operational Examples
Ground Plane Wire
Estimate inductance of a round wire routed above a conductive reference plane.
RF Layout
Change wire height, diameter and length to see inductance changes.
Diagrams & Theory
Wire over plane inductance depends on wire diameter, height above plane, length and magnetic permeability.
Formulas & Mathematical Logic
L = (μ0 × μr / 2π) × l × acosh(2h / d)
acosh(x) = log(x + sqrt(x² - 1))
μ0 = 4 × π × 10^-7 H/m
The calculator converts wire diameter, height, and length into meters first, then applies the wire-over-plane inductance expression.
Step-by-Step Example
Example: wire diameter d = 1 mm, height h = 10 mm, length l = 100 mm, relative permeability = 1.
Convert all dimensions into meters before using the formula.
Calculate the ratio 2h / d.
Apply acosh(2h / d), then multiply by length and permeability terms.
The final result is displayed in henries using scientific notation.
How to Use This Calculator
Enter the round wire diameter and select its unit.
Enter the height above the reference plane.
Enter the wire length running above the plane.
Enter relative permeability. Use 1 for air, copper wire, and common non-magnetic layouts.
Click Calculate to estimate the wire-over-plane inductance.
About This Calculator
Estimate inductance of a wire routed above a reference plane.
The CalcBoy Wire Over Plane Inductance Calculator helps estimate conductor inductance when a round wire runs above a conductive plane or PCB ground reference.
A wire over a plane behaves differently from an isolated wire because the reference plane provides a nearby return path. The height above the plane strongly affects magnetic field area, so raising the conductor usually increases inductance. Keeping the wire close to the plane can reduce loop inductance, which is useful in RF wiring, fast-switching power circuits, pulse layouts, and sensitive measurement setups.
This calculator is useful when checking short flying wires over ground planes, RF jumper wires, bus conductors over chassis metal, or prototype PCB layouts where a wire is used as a temporary trace. It gives a fast engineering estimate before measurement. Real-world results can change because of bends, nearby metal, solder pads, insulation shape, and the exact return-current path, so final hardware should still be verified when precision matters.
Best UseRound wire above ground plane, copper plane, chassis plate, or PCB reference plane.
Design InsightHigher wire height usually increases inductance because the return path is farther away.
Practical TipKeep high-current or fast-switching wires close to the reference plane to reduce voltage spikes.
Limit ReminderBends, vias, solder joints, and nearby conductors can shift real measured inductance.
Tip: In gate-drive, RF, and switching regulator prototypes, reducing wire height above the plane can be more effective than simply increasing wire diameter.
Frequently Asked Questions
What is wire over plane inductance?
It is the inductance of a round conductor routed above a conductive reference plane. The plane acts as the return-current reference and changes the magnetic field geometry.
Why does height above the plane matter?
Greater height increases the magnetic loop area between the wire and the return plane, which usually increases inductance.
What value should I use for relative permeability?
Use μr = 1 for air, copper, common insulation, PCB ground plane layouts, and most non-magnetic environments.
Can this be used for PCB wiring?
It can be used as a quick estimate for round wire jumpers over a PCB plane. Flat PCB traces need a trace or transmission-line calculator for better accuracy.
Does thicker wire reduce inductance?
For the same height and length, a larger wire diameter can reduce the calculated inductance because it changes the 2h / d ratio.
Why is the result in scientific notation?
Wire-over-plane inductance is often very small, so scientific notation keeps the henry value compact and readable.
Is this calculator exact for RF layouts?
No. It is a practical estimate. RF layouts should be verified with measurement or field-solver tools when tight impedance or inductance control is required.
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