Please enter all required values.
RESULTS
Input Parameters Specification
Trace WidthWidth of the stacked broadside PCB traces. Wider traces usually reduce inductance for the same spacing and length.
Trace SeparationVertical distance between upper and lower traces. Larger separation increases the inductance value in the preserved source formula.
Trace LengthCoupled trace length used directly in the final inductance equation. Longer coupled routing increases total inductance.
Relative PermeabilityMagnetic permeability ratio. Use 1 for standard PCB dielectric, FR4 region, air gap, and most non-magnetic PCB materials.
Practical Operational Examples
Broadside PCB Coupling
Estimate inductance between stacked traces in multilayer PCB layouts, especially when conductors overlap on adjacent layers.
Layout Optimization
Change width, spacing, length or permeability to see how broadside coupled trace inductance varies.
Switching Loop Review
Useful for compact power loops, pulse lines, current sense traces and dense multilayer routing where stacked conductors interact.
RF and High-Speed Boards
Use the result as a quick estimate before deeper electromagnetic simulation or lab measurement for critical layouts.
Diagrams & Theory
Broadside coupled traces are placed one above another. Their inductance depends on trace width, vertical separation, coupled length and relative permeability.
Formulas & Mathematical Logic
Formula used from source code: L = length × (μ0 × μr × separation / width)
μ0 = 4 × π × 10^-7 H/m.
Width, separation and length are converted to meters using the selected unit multipliers.
Relative permeability μr is entered directly. For normal PCB dielectric and air, μr is usually 1.
This version preserves the original JavaScript calculation behavior exactly.
Practical meaning: longer length and greater separation increase inductance, while wider traces reduce the calculated inductance.
Step-by-Step Example
Example: trace width = 2 mm, trace separation = 0.5 mm, trace length = 50 mm, relative permeability = 1.
The calculator converts width, separation and length from millimeters to meters.
μ0 is set as 4 × π × 10^-7 H/m.
Relative permeability is multiplied with μ0.
The formula multiplies length by μ0 × μr × separation / width.
The final inductance result is displayed in henries.
How to Use This Calculator
Enter the broadside trace width and select the correct unit.
Enter the vertical separation between the stacked traces.
Enter the coupled trace length.
Enter relative permeability. Use 1 for standard PCB material.
Click Calculate to get broadside coupled trace inductance.
Use the result to compare different width, spacing and routing length choices.
About This Calculator
Estimate inductance between stacked PCB traces in multilayer layouts.
The CalcBoy Broadside Coupled Trace Inductance Calculator calculates inductance from trace width, vertical separation, coupled length and relative permeability.
Broadside coupled traces are two conductors placed one above another on different PCB layers. This geometry appears in dense multilayer boards, current return structures, compact power routing, RF layouts, high-speed interconnects and prototype stackups where conductors overlap vertically. Because the magnetic field links through the space between the conductors, geometry changes can shift the inductance value.
This calculator helps compare layout options before final PCB routing. Increasing coupled length or vertical separation increases the calculated inductance in the preserved formula, while increasing trace width reduces it. For ordinary PCB dielectric or air regions, relative permeability is normally 1, so the main design variables are width, separation and length.
Use this value as a fast engineering estimate. Real PCB inductance also depends on return-path location, copper thickness, surrounding planes, vias, loop area, dielectric construction and frequency. For critical RF, switching, pulse or high-speed designs, validate with simulation, measurement or stack-up review.
Best UseBroadside-coupled PCB trace inductance estimates.
Supported InputsTrace width, separation, length and relative permeability.
Helpful ForMultilayer PCB layouts, RF traces, switching loops and high-speed routing.
Design ReminderShorter and wider traces usually reduce inductive effects.
Tip: In real PCB design, always check loop area and return-current path. A good nearby return path can matter more than conductor width alone.
Frequently Asked Questions
What is broadside coupled trace inductance?
It is the inductance estimated between two PCB traces stacked vertically on different layers.
What relative permeability should I enter?
Use 1 for normal PCB dielectric, FR4 region, air, and most non-magnetic materials.
Does longer trace length increase inductance?
Yes. In the preserved source formula, inductance is directly proportional to trace length.
Does wider trace reduce inductance?
Yes. A wider trace reduces the calculated inductance because width is in the denominator.
Can this replace electromagnetic simulation?
No. It is a quick estimate. Critical RF or high-speed layouts should be validated with simulation, measurement or stack-up review.
What unit is the result?
The output is displayed in henries.
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