Electrical

Solve for output voltage or either resistor in a two-resistor divider, with optional load to show the real-world loading effect.

voltage divider calculator

Find equivalent resistance for two or more resistors in parallel, with optional voltage to calculate total current and power.

parallel resistor calculator

Combine up to 10 resistors in series or parallel. Live SVG schematic, total resistance, conductance, and optional current and power from an applied voltage.

series resistor calculator

Calculate voltage, current, resistance, or power from any two known values using Ohm's Law and power formulas.

ohm's law calculator

Calculate the current-limiting resistor for an LED or LED chain from supply voltage, forward voltage, and forward current.

led resistor calculator

Calculate voltage drop over a wire run for single-phase or three-phase circuits, based on wire gauge, distance, and current.

voltage drop calculator

Find the minimum wire gauge (AWG) for a given load based on NEC 310.16 ampacity tables and voltage drop limits.

wire size calculator

Estimate the cost of running appliances based on wattage, usage hours, and electricity rate.

electricity cost calculator

Calculate electrical power. Convert watts to amps, amps to watts, and volts to watts for DC, single-phase, and three-phase AC circuits.

electrical power calculator

Decode resistor values from 4, 5, or 6 color bands, or find the color code for any resistance value and tolerance.

resistor color code calculator

Estimate how long a battery lasts from its capacity, the load it drives, efficiency, and an optional Peukert correction.

battery life calculator

Calculate frequency, period, duty cycle, and pulse width for the 555 timer IC in astable (oscillator) or monostable (one-shot) mode.

555 timer calculator

Design a first-order RC low-pass or high-pass filter. Solve for cutoff frequency, capacitance, or resistance, and read attenuation and phase at any probe frequency.

rc filter calculator

Calculate AC power factor, phase angle, apparent power, and reactive power. Size correction capacitors to improve PF for single-phase or three-phase systems.

power factor calculator

Combine inductors in series or parallel, and calculate stored energy, inductive reactance, and RL time constant. Live SVG schematic, smart unit formatting.

inductance calculator

Combine capacitors in series or parallel, and calculate stored charge Q = CV, energy E = ½CV², and the RC time constant. Live SVG schematic, smart unit formatting.

capacitance calculator