This page contains various javascript based calculators for electronics.

**Slim Jim and J-Pole antenna calculator**– Build a cactus for any frequency.**1/4 Wave Ground Plane antenna calculator**– Build a simple quarter wave with radials.**Ω Ohm’s Law Calculator Ω**– Enter 2 values from Voltage, Current, Power or Resistance, to find the remaining two.**dBm, dBW, µW, mW, W, kW and MW calculator**– Calculate between dBm, dBW, µW, mW, Watts, Kilowatts and Megawatts.**ERP & EIRP Calculator**– Calculate effective radiated power from your antenna.**Resonant Frequency Calculator**– Calculate the resonant frequency of a parallel inductor and capacitor tuned circuit.**PI attenuator calculator**– Calculate the resistor values for a PI attenuator.**T attenuator calculator**– Calculate the resistor values for a T attenuator.**Air cored inductor calculator**– Build an inductor of any value!**Inverted Vee Antenna**– Calculate the wire length for an inverted vee antenna.**Parallel Resistor, Inductor or series capacitor calculator**– Work out up to ten values, simply.**Electricity cost calculator**– Work out what an appliance costs to run if you know your electricity rate in kWh!