RF View

RF calculators

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

Every calculator runs in your browser, needs no account and shows the formula it uses, so you can check the result by hand. Each page also states the limits of the formula: the microstrip calculator, for example, uses the quasi-static Hammerstad and Jensen formulas, which ignore dispersion, so the impedance drifts at millimeter-wave frequencies, and the L-network calculator gives the narrowband lumped solution only.

The values were tested against known results before the pages went live. If a number looks wrong for your case, the matching tutorial explains the assumptions, for example VSWR, reflection coefficient and mismatch loss or microstrip width for 50 Ω on FR-4.

  • Attenuator Calculator: T-Pad and Pi-Pad Resistor Values2026-10-31A 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.
  • dBm to Watts, Volts and dBµV Converter2026-10-310 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.
  • L-Network Impedance Matching Calculator2026-10-31To 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).
  • Microstrip Impedance and Width Calculator (FR-4, Rogers)2026-10-31On 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.
  • Online S2P and Touchstone File Viewer2026-10-31Drop 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.
  • VSWR, Return Loss and Mismatch Loss Calculator2026-10-31Enter 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.