RF calculators

Free RF calculators with the formulas explained: VSWR and return loss, microstrip impedance, matching networks and more.

• Attenuator Calculator: T-Pad and Pi-Pad Resistor Values

  A 10 dB attenuator in a 50 Ω system is a T-pad of two 25.97 Ω series resistors with a 35.14 Ω shunt resistor, or a Pi-pad of two 96.25 Ω shunt resistors with a 71.15 Ω series resistor.

  Updated 2026-10-13

• dBm to Watts, Volts and dBµV Converter

  0 dBm is 1 mW, which is 224 mV rms (632 mV peak-to-peak, 107 dBµV) into 50 Ω. Every +3 dB doubles the power and every +10 dB multiplies it by 10, so 30 dBm is 1 W.

  Updated 2026-10-13

• L-Network Impedance Matching Calculator

  To match 50 Ω to 200 Ω at 1 GHz you need a network Q of 1.73: a 13.78 nH series inductor with a 1.378 pF shunt capacitor (low-pass), or a 1.838 pF series capacitor with an 18.38 nH shunt inductor (high-pass).

  Updated 2026-10-13

• Microstrip Impedance and Width Calculator (FR-4, Rogers)

  On 1.6 mm FR-4 a 50 Ω microstrip is about 3.06 mm wide (w/h 1.91, effective permittivity 3.33). Enter your substrate height and permittivity to get the width, impedance, guided wavelength and a quarter-wave length.

  Updated 2026-10-13

• Online S2P and Touchstone File Viewer

  Drop a Touchstone file (.s1p, .s2p, .s3p, .s4p) onto the viewer to plot it as magnitude, phase, VSWR, group delay or on a Smith chart. The file is processed in your browser and never uploaded.

  Updated 2026-10-13

• VSWR, Return Loss and Mismatch Loss Calculator

  Enter any one of VSWR, return loss, S11, |Γ|, mismatch loss or an impedance and get all the others. A 10 dB return loss is VSWR 1.92 and loses 0.46 dB to reflection; 20 dB is VSWR 1.22 and loses 0.044 dB.

  Updated 2026-10-13