Voltage Drop Calculator
Estimate voltage lost along a copper conductor using system voltage, current, one-way length, AWG size, system type, and an explicit temperature assumption.
EducationalOhm's Law Calculator
Solve a requested voltage, current, resistance, or power value from two compatible known electrical quantities.
EducationalWatts to Amps Calculator
Convert real power to current for DC, single-phase AC, or balanced three-phase AC with explicit voltage and power factor.
ReferenceResistor Color Code Calculator
Decode common 4-, 5-, and 6-band axial resistor colors, or encode an exactly representable resistance value.
Low Voltage EstimateLED Resistor Calculator
Estimate a series current-limiting resistor for one or more identical low-voltage DC LEDs connected in series.
EstimateBattery Runtime Calculator
Estimate runtime from battery energy, load power, conversion efficiency, and usable-capacity assumptions.
EducationalkWh Calculator
Calculate electrical energy in kilowatt-hours from device power and operating time, with an optional user-entered electricity rate.
EstimateSolar Panel Output Calculator
Estimate simple daily, monthly, and annual solar-panel energy from rated panel watts and user-supplied sun-hours and loss assumptions.
Circuit analysis calculators
Use ideal component relationships for resistor networks, dividers, RC behavior, and LC resonance. These are mathematical models, not safe-design certifications.
Parallel and Series Resistor Calculator
Calculate equivalent resistance from known series or parallel values.
Ideal circuit mathVoltage Divider Calculator
Calculate unloaded and optional loaded output voltage for an ideal two-resistor divider.
Ideal circuit mathRC Time Constant Calculator
Calculate RC time constant and ideal charging or discharging voltage over time.
Ideal circuit mathRC Filter Calculator
Calculate ideal first-order low-pass or high-pass cutoff and frequency response.
Ideal circuit mathLC Resonant Frequency Calculator
Solve ideal LC resonant frequency, inductance, or capacitance.
Scope decisions
The Wire Size candidate is deferred. Voltage-drop-only gauge selection would repeat the Voltage Drop calculator, while real conductor sizing also depends on ampacity, insulation and termination ratings, ambient conditions, conductor count, protection, load type, local amendments, and equipment rules.
Current code review
Code context was reviewed against the 2026 NFPA 70, National Electrical Code on September 1, 2026. Adoption varies: a state or local jurisdiction may use an earlier edition, amendments, or additional requirements.
Capacitor fundamentals
Capacitors in Series Calculator
Calculate equivalent capacitance for two to fifty ideal capacitors connected in series, with practical SI-prefix units.
Ideal component mathCapacitive Reactance Calculator
Calculate ideal capacitive reactance, capacitance, or frequency from the other two known values.