WebToolArcElectrical Tools
Free browser-based electrical tools with instant results and no account required.
Ohm's Law Calculator
Solve voltage, current, resistance, and power from any two known electrical values.
Electrical ToolsResistor Color Code Calculator
Decode common 4-band and 5-band resistor color codes into resistance and tolerance.
Electrical ToolsWatts Volts Amps Calculator
Convert between watts, volts, and amps for DC or simple AC power calculations.
Electrical ToolsVoltage Drop Calculator
Estimate conductor voltage drop from current, wire gauge, material, and one-way length.
Electrical ToolsElectricity Cost Calculator
Estimate electricity usage and cost from watts, hours per day, electricity rate, and days.
Electrical ToolsLED Resistor Calculator
Calculate a series resistor and resistor power for one or more LEDs in series.
Electrical ToolsVoltage Divider Calculator
Calculate unloaded or loaded resistor-divider output voltage, current, ratio, and power.
Electrical ToolsSeries Resistor Calculator
Add resistor values in series and inspect total resistance and current for an optional test voltage.
Electrical ToolsParallel Resistor Calculator
Calculate the equivalent resistance of two or more resistors connected in parallel.
Electrical ToolsCapacitor Series Parallel Calculator
Calculate equivalent capacitance for capacitors connected in series or parallel.
Electrical ToolsRC Time Constant Calculator
Calculate RC time constant, common charge timing points, and cutoff frequency.
Electrical ToolsRL Time Constant Calculator
Calculate an ideal RL time constant and common current-rise timing points.
Electrical ToolsResonant Frequency Calculator
Calculate the ideal resonant frequency of an LC circuit.
Electrical ToolsCapacitive Reactance Calculator
Calculate ideal capacitor reactance from frequency and capacitance.
Electrical ToolsInductive Reactance Calculator
Calculate ideal inductor reactance from frequency and inductance.
Electrical ToolsRLC Impedance Calculator
Calculate series RLC impedance magnitude, reactance, phase, and ideal resonance.
Electrical ToolsPower Factor Calculator
Calculate power factor, reactive power, and phase angle from real and apparent power.
Electrical ToolsmAh to Wh Calculator
Convert battery capacity from milliamp-hours to watt-hours using nominal voltage.
Electrical ToolsWh to mAh Calculator
Convert watt-hours to milliamp-hours at a chosen nominal voltage.
Electrical ToolsBattery Runtime Calculator
Estimate idealized battery runtime from capacity, voltage, load, efficiency, and usable fraction.