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.