Calculate it. Understand it. Verify it.
Free electrical engineering calculators for power systems, circuits, RF, energy, math, and student tools. NodeAndVolt provides transparent formulas, examples, and practical guides so users can calculate, understand, and verify results.
Popular Calculators
Ohm's Law Calculator
Find voltage, current, resistance, or power from any two values.
PopularThree-Phase Power Calculator
Calculate balanced kW and kVA from line voltage, current, and PF.
PopularVoltage Drop Calculator
Estimate conductor drop for DC, single-phase, or three-phase systems.
PopularTransformer kVA Calculator
Calculate transformer apparent power from voltage and current.
PopularMotor FLA Calculator
Estimate motor running current from horsepower, voltage, efficiency, and PF.
PopularResistor Color Code Calculator
Decode 4-band and 5-band resistor values.
PopularBattery Runtime Calculator
Estimate how long a battery can power a load.
PopularPower Factor Correction Calculator
Estimate the capacitor kVAR needed to improve power factor.
19 featured tools shown.
NodeAndVolt Workbench
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Focused Calculator Hubs
Use these topic pages when you want a guided path through related tools and guides.
Explore by Discipline
Power Systems
Three-phase systems, transformers, motors, generation, fault analysis, and distribution.
16 tools and guidesCircuits and Electronics
Ohm's law, components, transient response, phasors, and practical electronics.
9 tools and guidesSignals and Systems
Waveforms, reactance, resonance, phasors, vectors, and frequency response.
6 tools and guidesRF and Electromagnetics
RF power, antennas, EIRP, arrays, propagation, phasors, vectors, and skin depth.
13 tools and guidesEnergy and Renewables
Batteries, solar, energy conversion, efficiency, and cost.
4 tools and guidesStudent Toolkit
Weighted grades, GPA, math helpers, and study calculations.
2 academic toolsFeatured Tools
3-Phase Power
Calculate balanced kW and kVA.
Bulk powerBulk Power MVA and Amps
Convert between line MVA and current.
Fault analysisTransformer Fault Current
Estimate terminal current from percent impedance.
Power flowMW, MVAR, MVA, and PF
Solve real, reactive, and apparent power.
Power systemsTransformer kVA
Calculate transformer apparent power.
MachinesMotor FLA
Estimate motor running current.
CircuitsOhm's Law
Calculate V, I, R, and P.
ElectronicsResistor Color Code
Decode 4-band and 5-band values.
DistributionVoltage Drop
Estimate conductor loss.
SignalsLC Resonance
Find ideal resonant frequency.
SignalsWaveform Conversion
Convert RMS, peak, and peak-to-peak.
RF powerdBm to Watts
Convert logarithmic RF power to standard units.
RF propagationFree Space Path Loss
Estimate ideal wireless path attenuation.
AntennasQuarter-Wave Antenna
Estimate quarter, half, and full-wave lengths.
AC and signalsPhasor Calculator
Convert and combine complex magnitude-angle values.
RF link budgetsEIRP Calculator
Combine transmit power, feed loss, and gain.
Antenna arraysLinear Array Factor
Evaluate ideal array reinforcement.
MathMath Solver
Scientific math, trig, derivative, and integral tools.
EnergyBattery Runtime
Estimate stored-energy duration.
EnergySolar Array Sizing
Estimate array power and panel count.
StudentsWeighted Grade Calculator
Calculate current and required grades.
StudentsGPA Calculator
Calculate term and cumulative GPA.
Recent Calculations
Calculators and Guides Work Together
Transparent math
See formulas and substituted values rather than an unexplained answer. Read the calculation methodology.
Companion guides
Relevant calculators link directly to theory, assumptions, and common mistakes.
Privacy by default
Inputs run locally. Location is not requested, and student data is not preloaded or submitted.
Frequently Asked Questions
What can I calculate here?
Power, faults, transformers, circuits, RF links, antennas, batteries, solar, math, and school-grade tools.
How are the tools organized?
Tools are grouped by discipline, with related calculators and guides linked together so you can move from a result to the formulas, assumptions, and related topics.
Will new tools keep getting added?
Yes. New pages should deepen the existing power, circuits, RF, energy, math, and student-tool coverage.
Can I trust the answers?
The tools are meant for educational and estimation use. Verify final values against applicable codes and equipment ratings.