Please enter all required values.
Formulas & Mathematical Logic
Formula used from source code: L = 0.00508 × b × (log(2 × b / (w + h)) + 0.5 + 0.2235 × (w + h) / b)
Where b = strip length in inches, w = strip width in inches, h = distance in inches.
Output inductance is shown in microhenries.
Practical meaning: increasing strip length raises inductance, while increasing conductor width usually helps reduce the inductive effect.
Step-by-Step Example
Example: strip width = 0.1 in, strip length = 2 in, distance = 0.05 in.
The calculator reads all three dimensions directly in inches.
The strip length value is used as b in the original formula.
The strip width and distance are combined as w + h inside the logarithmic term.
The final output is calculated and displayed in microhenries.
About This Calculator
Estimate PCB microstrip parasitic inductance from simple trace geometry.
The CalcBoy Microstrip Inductance Calculator calculates strip inductance from conductor width, strip length and distance using the supplied PCB trace inductance formula.
Every PCB trace has parasitic inductance. In slow DC wiring it may be ignored, but in RF circuits, switching regulators, fast gate-drive paths and pulse circuits, even a small amount of trace inductance can create overshoot, ringing, EMI and unwanted voltage spikes. A long narrow route behaves more inductively than a short wide copper path.
This calculator is useful for RF PCB layouts, SMPS design, MOSFET gate loops, high-speed digital traces, antenna feeds, matching networks and general PCB troubleshooting. By changing strip width, strip length and distance, you can quickly see how the estimated inductance moves. It is especially helpful when comparing layout options before final routing.
For practical design, treat this result as an estimate. Real PCB inductance also depends on return path location, ground plane continuity, nearby copper, vias, loop area and frequency-dependent effects. For high-speed or RF production designs, combine this estimate with layout best practices and measurement or simulation where needed.
Best UsePCB trace inductance checks for RF, switching and pulse layouts.
Supported InputsStrip width, strip length and distance in inches.
Helpful ForSMPS loops, MOSFET gates, RF traces, antenna feeds and high-speed signals.
Design ReminderShorter, wider traces with tight return paths usually reduce inductance.
Tip: In switching circuits, reduce loop area first. A short current path with a nearby return plane often matters more than only increasing copper width.
Frequently Asked Questions
What is microstrip inductance?
Microstrip inductance is the parasitic inductance of a PCB trace caused by current flow and the magnetic field around the conductor.
Does a longer PCB trace increase inductance?
Yes. Longer conductors generally increase inductance and can create more ringing or voltage spike problems in fast circuits.
Does wider copper reduce inductance?
Usually yes. A wider trace tends to reduce inductance compared with a narrow trace of the same length.
Why does trace inductance matter in switching circuits?
Trace inductance can cause voltage overshoot, ringing, EMI and stress on MOSFETs, diodes and drivers during fast current changes.
Can this calculator replace RF simulation?
No. It gives a simple estimate. Critical RF or high-speed designs should also use simulation, measurement and manufacturer stack-up data.
What unit is the output?
The result is shown in microhenries.