PCB Via Inductance Calculator
Estimate via inductance, inspect reactance at your frequency, and compare practical geometry changes. Includes a frequency sweep and a clear explanation of what the model excludes.
Method & assumptions ↓02 · Understand the result
Calculate to see your estimate, frequency curve and geometry comparison.
Via geometry
Conductive barrel and connected span
Calculate to show dimensions.
Return path matters
Conceptual return path — not a field solution
METHOD & SOURCES
How the estimate works
With h and d in millimetres, L in nH is 0.2 × h × [ln(4h/d) + 1]. This is the via approximation published in TI SLLA284G, Equation 2, page 16. ln is the natural logarithm.
L [nH] = 0.2 × h [mm] × [ln(4h/d) + 1]
X [Ω] = 2π × f [Hz] × L [H]
The diameter is a geometric approximation to the conductive barrel. Pad size, antipad clearance, plating distribution and nearby copper are not separate inputs to this model.
This tool accepts 0.01–100 mm geometry and screens out h < d. These are conservative application limits for this calculator, not manufacturing capabilities or a validated accuracy range.
Inductive reactance is X = 2πfL, with frequency in Hz and inductance in H. At DC, ideal reactance is zero; real resistance remains outside this calculation.
The optional rise-time mode uses f = 0.35/tr for a single-pole 10–90% bandwidth estimate. Other edge shapes use other conventions. Enter a known frequency whenever it is available.
A real transition depends on its return path and surrounding planes. Mutual inductance, parallel vias, capacitance, resonance and frequency-dependent losses require a more complete model.
Worked example: length, diameter and return paths →
Published by HilPCB · Method reviewed November 8, 2026
COMMON QUESTIONS
PCB via inductance questions
Is this the signal-loop inductance?
No. This is an isolated-via geometry estimate. The actual loop includes the return path; nearby return vias and plane continuity can materially change it.
Should I use board thickness or via length?
Use the conductive span between the layers being connected. It can equal board thickness for a through connection; a blind connection can be shorter.
Why does rise-time mode differ from other calculators?
A rise time does not define one unique frequency. This tool states the 0.35/tr single-pole bandwidth convention; some tools use 0.5/tr. At the same actual frequency and geometry, X = 2πfL is unchanged.
Does twice the via count halve inductance?
Not generally. Mutual coupling and shared return paths affect the array. This tool does not apply a 1/N inductance rule.
Can I use this above 10 GHz?
The frequency control is limited to 10 GHz. Even below that limit, the fixed-L model may miss capacitance and resonance; use a field solver or measured data for high-frequency verification.