Electrical Calculators
Capacitive Reactance Calculator
Calculate capacitive reactance (Xc) in ohms from AC frequency and capacitance, showing how capacitors oppose alternating current.
Capacitor Energy Calculator
Calculate the charge and energy stored in a capacitor from its capacitance and voltage.
Circuit Breaker Sizing Calculator
Calculate the minimum circuit breaker rating required for a continuous electrical load using the standard 125% sizing rule.
Circuit Power Calculator
Compute apparent, real, and reactive power in an AC circuit from voltage, current, and power factor, with typical power factor reference values shown.
Electric Field Calculator
Find electric field strength from force and charge, or from a point charge using Coulomb's law, with reference field strength comparisons shown.
Electrical Energy Cost Calculator
Calculate the daily and monthly running cost of any electrical appliance from its wattage, daily usage hours, and your electricity rate.
Electrical Load Calculator
Total appliance loads, apply a demand factor, and convert the result to circuit current draw at a given voltage for panel and circuit sizing work.
Inductive Reactance Calculator
Calculate inductive reactance (XL) in ohms from AC frequency and inductance, showing how inductors oppose alternating current.
Magnetic Field Calculator
Calculate magnetic flux density for a straight wire, the center of a circular loop, or inside a solenoid, with real-world flux density comparisons shown.
Ohm's Law Calculator
Solve for voltage, current, or resistance using Ohm's Law, with a worked numeric example and the full formula substitution shown step by step here.
Parallel Resistance Calculator
Calculate the total combined resistance of two resistors wired in parallel.
Power Factor Calculator
Calculate power factor and phase angle from real power, voltage, and current to check AC circuit efficiency.
RC Time Constant Calculator
Calculate the RC time constant of a resistor-capacitor circuit to determine charge and discharge timing.
Resistor Calculator
Combine resistors in series or parallel to find total equivalent resistance, with the underlying formulas and a fully worked numeric example included.
Three-Phase Power Calculator
Calculate real power in a balanced three-phase electrical system from line voltage, line current, and power factor.
Transformer Rating Calculator
Calculate the required transformer VA rating, turns ratio, and primary current from secondary voltage and current on an ideal transformer setup.
Voltage Divider Calculator
Calculate the output voltage of a two-resistor voltage divider circuit from input voltage and resistor values.
Voltage Drop Calculator
Estimate voltage drop and percent drop across a copper conductor by wire gauge, length, current, and phase, checked against the 3% design guideline.
Wattage Calculator
Calculate electrical power from voltage, current, or resistance in watts, and compare the result against typical household appliance wattage ranges.
Wire Size Calculator
Match load current to a minimum copper wire gauge using a simplified NEC ampacity table, with the 125% continuous-load design rule applied here.
Electricity Follows Fixed Rules
Unlike many practical estimates, electrical calculations are governed by exact physical laws — Ohm's law, power equations, and wire resistance tables leave little room for approximation, which is exactly why getting them right matters. These ten calculators cover the core electrical engineering math from basic circuits to wiring.
Why Wire Length and Gauge Both Matter
Most electrical codes recommend keeping voltage drop under 3% for branch circuits — past that, appliances and lighting can underperform even though the circuit is technically still "working." The Voltage Drop Calculator and Wire Size Calculator together confirm whether a run needs a thicker gauge before installation, not after.
Popular Electrical Calculators
- Ohm's Law Calculator — solves for voltage, current, or resistance given the other two values.
- Wattage Calculator — converts between voltage, current, and power.
- Transformer Rating Calculator — sizes a transformer's kVA rating to a given load.
Related: Mechanical Engineering Calculators, Physics Calculators for the underlying field equations.