Electrical
Free electrical engineering calculators: Ohm's Law, wire sizing, voltage drop, resistor color codes, 555 timer, power factor, RC filters, and more.
Calculators
Electricity Cost Calculator
Estimate the cost of running appliances based on wattage, usage hours, and electricity rate.
Open Calculator →Ohm's Law Calculator
Calculate voltage, current, resistance, or power from any two known values using Ohm's Law and power formulas.
Open Calculator →Power Calculator
Calculate electrical power. Convert watts to amps, amps to watts, and volts to watts for DC, single-phase, and three-phase AC circuits.
Open Calculator →Wire Size Calculator
Find the minimum wire gauge (AWG) for a given load based on NEC 310.16 ampacity tables and voltage drop limits.
Open Calculator →Voltage Drop Calculator
Calculate voltage drop over a wire run for single-phase or three-phase circuits, based on wire gauge, distance, and current.
Open Calculator →Resistor Color Code Calculator
Decode resistor values from 4, 5, or 6 color bands, or find the color code for any resistance value and tolerance.
Open Calculator →Voltage Divider Calculator
Solve for output voltage or either resistor in a two-resistor divider, with optional load to show the real-world loading effect.
Open Calculator →LED Resistor Calculator
Calculate the current-limiting resistor for an LED or LED chain from supply voltage, forward voltage, and forward current.
Open Calculator →Battery Life Calculator
Estimate how long a battery lasts from its capacity, the load it drives, efficiency, and an optional Peukert correction.
Open Calculator →555 Timer Calculator
Calculate frequency, period, duty cycle, and pulse width for the 555 timer IC in astable (oscillator) or monostable (one-shot) mode.
Open Calculator →Resistor Network 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.
Open Calculator →RC Filter 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.
Open Calculator →Power Factor 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.
Open Calculator →Inductance Calculator
Combine inductors in series or parallel, and calculate stored energy, inductive reactance, and RL time constant. Live SVG schematic, smart unit formatting.
Open Calculator →Capacitance 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.
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