Electronics calculators
Free, no-signup calculators for the electronics bench — resistors, LEDs, dividers and Ohm's law. Everything runs in your browser; nothing is uploaded.
Tools
Resistor color code calculatorDecode 4, 5 and 6-band resistors or enter ohms to get the band colors — plus a printable chart.Ohm's law calculatorEnter any two of voltage, current, resistance and power — solve the other two with the formula shown.Parallel resistor calculatorSeries and parallel equivalents, plus two E24 parts that hit any exact target value.Voltage divider calculatorUnloaded and loaded Vout, string current, and the R2 for a target output snapped to E24.LED resistor calculatorMinimum ohms, next E24 value up, actual current and wattage for any supply and LED color.