Impedance Calculator

The impedance calculator converts series R + jX values — the numbers you read directly from NanoVNA-H markers in Smith or R+jX format — into every common RF figure of merit. Enter your measured impedance below to see all derived parameters at once.

Impedance Calculator

Impedance (series form)

R (resistance)

Ω

X (reactance)

jΩ

Z₀ (reference)

Ω

Quick pick: 50Ω 75Ω Open Short 25+j25Ω

Calculated Results

SWR

—

Return Loss

—

dB

Reflection Coefficient

—

Mismatch Loss

—

dB

Parallel Equivalent

—

Smith Chart Position

—

Reading Impedance from NanoVNA-H

Impedance values come from the NanoVNA-H in several ways:

1. Smith Chart markers — set a marker on the S11 trace and switch format to R+jX (MARKER > FORMAT > R+jX)
2. Shell command — after a sweep, data 0 returns raw S11 complex pairs; impedance is derived from the reflection coefficient
3. PC software — NanoVNASaver, NanoVNASharp, and similar tools display impedance alongside the Smith Chart

The calculator accepts the series form (R + jX) because that is what NanoVNA-H displays at each marker. If your impedance source gives parallel form, convert first or use the parallel equivalent output from this calculator in reverse.

What Each Output Means

Output	What It Tells You
SWR	Standing wave ratio — 1.0 is perfect, below 2.0 is generally acceptable
Return Loss	Power reflected back, in dB — higher is better (more power delivered to load)
Reflection Coefficient	Complex ratio Γ = (Z - Z₀) / (Z + Z₀), magnitude 0–1
Mismatch Loss	Power lost due to impedance mismatch, in dB — always ≥ 0
Parallel Equivalent	Same impedance expressed as parallel Rp ‖ Xp — useful for matching network design
Smith Chart Position	Which quadrant/region the impedance falls in — inductive, capacitive, inside/outside the SWR circle

Tip

For matching network design, you often need the parallel form. The NanoVNA-H only displays series R + jX, so this calculator bridges that gap.

Practical Use Cases

Checking an Antenna

Measure S11 at your target frequency. Enter the R + jX reading here to instantly see whether SWR is acceptable and how much power you are losing to mismatch. An antenna reading of 50 + j0 Ω is perfect — the calculator will show SWR = 1.00 and zero mismatch loss.

Designing a Matching Network

You need the parallel equivalent impedance to design L-networks and pi-networks. Enter your load impedance, note the parallel form, then calculate component values for your matching topology.

Verifying Calibration Standards

A known 50 Ω load should read very close to 50 + j0. Enter the measured value — if SWR is above 1.05, your calibration standards or cables may need attention.

Related Guides

• Smith Chart Marker Formats — understanding NanoVNA-H impedance display modes
• LC Matching — using the firmware’s built-in LC match calculator
• Smith Chart Primer — how impedance maps to the Smith Chart