45 FREE TOOLS

Electrical, made clearer.

Calculate ideal circuit values, power, batteries, impedance and electrical energy with explicit units.

Tools in this category

Ohm’s Law Current Calculator

Find current through a known resistance at a given voltage.

Ohm’s Law Voltage Calculator

Find voltage drop across a resistor carrying a given current.

Ohm’s Law Resistance Calculator

Find resistance from measured DC voltage and current.

DC Power Calculator

Calculate electrical power from voltage and current.

Resistor Power Dissipation Calculator

Find ideal resistive heating from current and resistance.

Voltage Divider Calculator

Find unloaded output voltage from a two-resistor divider.

Current Divider Calculator

Find branch current through R1 in a two-resistor parallel circuit.

Series Resistance Calculator

Find equivalent resistance of three resistors in series.

Parallel Resistance Calculator

Find equivalent resistance of two parallel resistors.

Series Capacitance Calculator

Find equivalent capacitance of two series capacitors.

Parallel Capacitance Calculator

Find equivalent capacitance of two parallel capacitors.

Capacitor Charge Calculator

Find charge stored by a capacitor at a specified voltage.

Capacitor Energy Calculator

Find electrical energy stored in an ideal capacitor.

Inductor Energy Calculator

Find magnetic energy stored in an ideal inductor.

RC Time Constant Calculator

Find the characteristic time for a resistor-capacitor circuit.

RL Time Constant Calculator

Find the characteristic time for a resistor-inductor circuit.

Capacitor Charging Voltage Calculator

Find capacitor voltage after an ideal DC charging step.

Capacitor Discharging Voltage Calculator

Find remaining capacitor voltage during resistive discharge.

Capacitive Reactance Calculator

Find a capacitor’s reactance magnitude at an AC frequency.

Inductive Reactance Calculator

Find an inductor’s reactance at an AC frequency.

LC Resonant Frequency Calculator

Find ideal resonance from inductance and capacitance.

RC Filter Cutoff Frequency Calculator

Find the −3 dB cutoff of a first-order RC filter.

RL Filter Cutoff Frequency Calculator

Find the corner frequency of an ideal first-order RL filter.

Series RLC Impedance Calculator

Find the impedance magnitude of a series RLC network.

Single-Phase AC Real Power Calculator

Find active power from RMS voltage, RMS current and power factor.

Balanced Three-Phase Power Calculator

Find real power from line voltage and line current.

Reactive Power Calculator

Find reactive power magnitude from apparent power and power factor.

Sine Wave RMS Voltage Calculator

Convert a sinusoid’s peak voltage to RMS voltage.

Sine Wave Peak Voltage Calculator

Find peak voltage from sinusoidal RMS voltage.

Battery Energy Calculator

Estimate nominal battery energy from voltage and amp-hours.

Battery Runtime Calculator

Estimate load runtime from usable stored energy and load power.

Battery Charge Time Calculator

Estimate constant-current charging time for a capacity increment.

Electricity Cost Calculator

Estimate energy cost for one appliance over a specified duration.

Ideal Transformer Voltage Calculator

Find secondary voltage from a transformer’s turns ratio.

LED Series Resistor Calculator

Estimate a resistor for an ideal LED voltage-drop model.

Inverting Op-Amp Gain Calculator

Find ideal closed-loop gain from feedback and input resistors.

Non-Inverting Op-Amp Gain Calculator

Find ideal non-inverting amplifier gain.

Voltage Gain in Decibels Calculator

Express a positive voltage ratio in decibels.

Power Gain in Decibels Calculator

Express a positive power ratio in decibels.

dBm to Watts Calculator

Convert a power level referenced to one milliwatt into watts.

Watts to dBm Calculator

Express positive power in decibels referenced to one milliwatt.

Wire Resistance Calculator

Estimate resistance from material resistivity and conductor geometry.

DC Resistive Voltage Drop Calculator

Find voltage loss across a known total path resistance.

Parallel Plate Capacitance Calculator

Estimate capacitance for two large parallel plates with a dielectric.

Uniform Electric Field Calculator

Find field magnitude between equipotential parallel plates.

Choosing a tool for electrical

Choose the circuit relationship you need and distinguish DC values, sinusoidal RMS values and peak values. Component ratings and installation safety require separate assessment.

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