100 Amp Wire Size Calculator
Calculate the correct wire gauge for 100-amp circuits. NEC ampacity tables for copper and aluminum conductors with voltage drop analysis.
Free Electromagnetism Calculators
88 toolsCircuit, capacitor, resistor, magnetic field, and electromagnetic wave calculators. Browse our free electromagnetism tools below — no sign-up required.
12V Wire Size Calculator
Calculate correct wire gauge for 12V DC systems. Automotive, solar, marine, and LED applications with voltage drop analysis.
220V Wire Size Calculator
Calculate wire gauge for 220/240V circuits. Size conductors for appliances, HVAC, EV chargers, and welders with NEC ampacity tables.
24V Wire Size Calculator
Calculate wire gauge for 24V systems. HVAC thermostats, landscape lighting, sprinkler valves, and access control with voltage drop limits.
3-Phase Motor Amperage Calculator
Calculate 3-phase motor full-load amps from HP, voltage, efficiency, and power factor. NEC Table 430.250 lookup and breaker sizing.
AC Wattage Calculator
Calculate AC power: real watts, reactive VAR, and apparent VA from voltage, current, and power factor. Single and 3-phase with cost estimation.
Acoustic Impedance Calculator
Calculate acoustic impedance Z = ρv, reflection and transmission coefficients at material boundaries. Includes material database for ultrasound.
Amp to Wire Size Calculator
Convert amperage to wire gauge using NEC ampacity tables. Copper and aluminum, temperature ratings, conduit fill, and ambient temperature derating.
Beat Frequency Calculator
Calculate beat frequency from two interfering waves. Visualize amplitude modulation, cents difference, and musical interval analysis.
Capacitance Calculator
Calculate capacitance for parallel plate, cylindrical, and spherical capacitors. Dielectric materials, stored charge, energy, and electric field.
Capacitive Reactance Calculator
Calculate capacitive reactance Xc = 1/(2πfC), impedance, phase angle, and cutoff frequency. Frequency response and standard capacitor tables.
Capacitive Transformerless Power Supply Calculator
Design a capacitive dropper transformerless power supply. Calculate X-rated capacitor, surge resistor, zener, and component ratings.
Capacitor Calculator
Calculate capacitor charge, energy, time constant, reactance, and series/parallel combinations. RC discharge curve and standard value reference.
Capacitor Charge Time Calculator
Calculate how long a capacitor takes to charge or discharge through a resistor to a target voltage. RC time constant, milestones, and curve.
Capacitor Size Calculator
Calculate the right capacitor size for power factor correction, motor start/run, DC filtering, and audio crossover applications.
Capacitors in Series Calculator
Calculate equivalent capacitance, voltage distribution, and energy for capacitors in series. Visual voltage distribution and per-capacitor breakdown.
Coefficient of Discharge Calculator
Calculate coefficient of discharge (Cd), theoretical and actual flow rates for orifices, nozzles, weirs, and Venturi meters.
Compton Wavelength Calculator
Calculate the Compton wavelength λ_C = h/(mc) for any particle. Explore Compton scattering angles, rest energies, and quantum length scales.
Conductivity to Resistivity Calculator
Convert between electrical conductivity (σ) and resistivity (ρ). Material database, temperature correction, %IACS, and wire resistance.
Critical Damping Calculator
Calculate critical damping coefficient, damping ratio, natural frequency, quality factor, and transient response for second-order systems.
Current Divider Calculator
Calculate branch currents in parallel resistor networks using the current divider rule. Supports any number of resistors with power analysis.
Cutoff Frequency Calculator
Calculate cutoff frequency for RC, RL, and RLC filters. Solve for any component value. Frequency response table and filter design.
Cyclotron Frequency Calculator
Calculate cyclotron (gyro) frequency, Larmor radius, and relativistic corrections for charged particles in magnetic fields.
Damping Ratio Calculator
Calculate damping ratio (ζ) from system parameters, peak amplitudes, or RLC values. Quality factor, settling time, and response analysis.
DC Wire Size Calculator
Calculate correct wire gauge for DC systems with voltage drop limits. Solar, battery, automotive, marine, and LED wire sizing.
De Broglie Wavelength Calculator
Calculate the de Broglie wavelength λ = h/p for any particle. Relativistic support, multiple input modes, energy scans, and scale comparisons.
Electric Field of a Point Charge Calculator
Calculate electric field E = kQ/r² for single or multiple point charges. Includes superposition, dielectric media, and field vs distance tables.
Faraday's Law EMF Calculator
Calculate induced EMF using Faraday's law of electromagnetic induction: ε = −NdΦ/dt. Supports flux, field, and motional EMF modes.
Frequency Bandwidth Calculator
Calculate bandwidth, Q factor, and cutoff frequencies for resonant circuits and filters. Frequency response table, RLC values, and selectivity analysis.
Frequency of Light Calculator
Calculate light frequency from wavelength using f = c/λ. Visible spectrum color mapping, photon energy in eV, wave number, and electromagnetic spectrum reference table.
Frequency to Wavelength Calculator
Convert frequency to wavelength for light, sound, and radio waves using λ = v/f. Supports EM waves, sound in air with temperature correction, and custom media.
Gauss's Law Calculator
Calculate electric flux and electric field using Gauss's law Φ = Q/ε₀. Supports spherical, cylindrical, and planar symmetries with dielectric materials.
Heat Capacity Calculator
Calculate heat energy Q = mcΔT, heat capacity, and heating time. Compare specific heats of common materials. Includes energy cost estimation and unit conversions.
Hohmann Transfer Orbit Calculator
Calculate Δv, transfer time, and propellant mass for Hohmann transfer orbits between two circular orbits. Supports Earth, Mars, Moon, and custom central bodies.
HP to Amps Calculator
Convert horsepower to amps for single-phase and three-phase motors. Accounts for motor efficiency and power factor. Includes NEMA reference tables.
Ideal Transformer Calculator
Calculate transformer voltage, current, and turns ratio using V₁/V₂ = N₁/N₂. Step-up, step-down, impedance matching. Includes efficiency and power loss.
Inductive Reactance Calculator
Calculate inductive reactance X_L = 2πfL, impedance, phase angle, and Q factor. Frequency response table shows how inductors behave across frequencies.
Internal Resistance Calculator
Find battery or source internal resistance from open-circuit and loaded voltage. Includes power loss, efficiency, short-circuit current, and maximum power transfer analysis.
J-Pole Antenna Calculator
Calculate J-pole antenna dimensions for any frequency. Get radiator length, stub length, gap, and feed point for VHF/UHF bands.
kVA to Amperage Calculator
Convert kVA to amps for single-phase and three-phase systems. Includes power factor, wire sizing, breaker selection, and power triangle.
LC Filter Calculator
Design LC low-pass and high-pass filters. Calculate inductance, capacitance, cutoff frequency, and Butterworth component values up to 5th order.
LED Resistor Calculator
Calculate the correct resistor value for any LED circuit. Supports series and parallel configurations, multiple LEDs, and nearest E24 standard values.
Magnetic Declination Calculator
Calculate magnetic declination for any location and date. Convert between true north and magnetic north bearings with compass correction.
Magnetic Dipole Moment Calculator
Calculate magnetic dipole moment, axial and equatorial fields, torque, and potential energy for current loops and coils.
Magnetic Field of Straight Wire Calculator
Calculate the magnetic field around a current-carrying wire using the Biot-Savart law. Supports infinite and finite wire models with permeability.
Magnetic Moment Calculator
Calculate magnetic moment, torque, and potential energy for current loops in external fields. Supports circular, square, and rectangular loops.
Magnetic Permeability Calculator
Calculate magnetic permeability, flux density, and core amplification. Compare diamagnetic, paramagnetic, and ferromagnetic materials.
MOSFET Threshold Voltage Calculator
Calculate MOSFET threshold voltage, drain current, operating region, transconductance, and overdrive voltage for NMOS and PMOS enhancement-mode transistors.
Natural Frequency Calculator
Calculate natural frequency, angular frequency, damping ratio, and period for spring-mass, pendulum, LC circuit, and cantilever beam systems.
Ohm's Law Calculator
Calculate voltage, current, resistance, and power with Ohm's Law. Includes energy cost estimation, AWG wire gauge recommendation, complete formula reference table, and collapsible wire sizing chart.
Parallel Capacitor Calculator
Calculate total capacitance for 2-10 capacitors in parallel, with reactance, energy storage, charge, and comparison to series configuration.
Parallel Inductors Calculator
Calculate total inductance for 2-6 inductors in parallel, with current distribution, reactance, energy storage, and mutual coupling analysis.
Parallel Resistor Calculator
Calculate total resistance for 2-10 resistors in parallel, with current distribution, power budget, nearest E24 standard value, and series comparison.
Porosity & Permeability Calculator
Calculate flow rate, Darcy velocity, pore velocity, and hydraulic conductivity using Darcy's law for porous media. Includes Kozeny-Carman estimation.
RC Circuit Calculator
Calculate RC time constant, charging/discharging curves, frequency response, energy storage, and settling time for resistor-capacitor circuits.
RC Filter Calculator
Design low-pass and high-pass RC filters with cutoff frequency, frequency response table, gain/phase analysis, and multi-stage cascading support.
Resistor Color Code Calculator
Decode 4, 5, or 6-band resistor color codes to find resistance, tolerance, and temperature coefficient. Visual resistor diagram included.
Resistor Noise Calculator
Calculate Johnson-Nyquist thermal noise voltage and current for any resistor. Includes spectral density, SNR, and noise vs. bandwidth tables.
Resistor Wattage Calculator
Calculate power dissipated by a resistor and find the correct wattage rating. Includes derating curves, safety factors, and standard ratings.
Resonant Frequency (LC) Calculator
Calculate LC tank circuit resonant frequency, quality factor, bandwidth, and characteristic impedance. Includes frequency sweep table and Q factor visualization.
RLC Circuit Calculator
Analyze RLC series and parallel circuits. Calculate impedance, phase, resonant frequency, Q factor, damping ratio, and frequency response with voltage distribution tables.
RLC Impedance Calculator
Calculate RLC circuit impedance Z = √(R² + (X_L − X_C)²), phase angle, current, power factor, and voltage distribution with impedance triangle visualization.
RMS Voltage Calculator
Calculate RMS voltage from peak voltage for sine, square, triangle, sawtooth, and rectified waveforms. Includes form factor, crest factor, and waveform comparison table.
Rolling Resistance Calculator
Calculate rolling resistance force F = C_rr × N for vehicles. Includes tire type and surface material comparison, grade resistance, power requirements, and per-tire force breakdown.
Series Inductors Calculator
Calculate total inductance of series-connected inductors with optional mutual inductance. Supports up to 8 inductors with aiding/opposing coupling and parallel equivalent comparison.
Series Resistor Calculator
Calculate total resistance of series resistors with voltage division. Supports up to 8 resistors with voltage drops, power dissipation, and visual breakdown of each resistor.
SLED (Superluminescent LED) Calculator
Calculate SLED characteristics including spectral width, coherence length, power spectral density, coupling efficiency, and wall-plug efficiency with source comparison table.
Solenoid Inductance Calculator
Calculate solenoid inductance L = μ₀μᵣN²A/l with Nagaoka correction. Compare core materials, view scaling relationships, and compute magnetic field and stored energy.
Solenoid Magnetic Field Calculator
Calculate magnetic field B = μ₀nI inside a solenoid. Includes field intensity H, magnetic flux, inductance, stored energy, field strength scale, and parameter sensitivity table.
Sound Wavelength Calculator
Calculate sound wavelength from frequency or vice versa. Supports 9 media (air, water, steel, etc.), temperature correction, musical note presets, and a multi-media comparison table.
Spherical Capacitor Calculator
Calculate capacitance of a spherical capacitor from inner/outer radii and dielectric. Includes charge, energy, E-field, surface charge density, cross-section visual, and dielectric comparison table.
Thermal Resistance Calculator
Calculate thermal resistance for up to 6 stacked layers. Includes temperature profile, layer breakdown, heat flux, status indicator, and presets for CPU, LED, and MOSFET thermal paths.
Transformer Sizing Calculator
Size a transformer by specifying voltages, power, and frequency. Calculates turns ratio, core area product, wire gauge, flux density margin, and compares 5 core materials.
Voltage Divider Calculator
Calculate output voltage from R1/R2 or design resistor values for a target voltage. Features load analysis, E24 nearest values, tolerance sensitivity, ratio visual, and common presets.
Voltage Drop Calculator
Calculate voltage drop in electrical wiring by AWG, distance, current, and conductor material. NEC compliance check, AWG comparison table, power loss, and transmission efficiency.
Voltage Regulation Calculator
Calculate voltage regulation percentage, output impedance, and power loss. Measure mode analyzes supply quality; design mode computes LDO requirements. Includes regulation quality rating and load s...
Volts to Electron-Volts Calculator
Convert between electron-volts, joules, temperature, and photon wavelength. Includes voltage-to-energy conversion, particle rest mass table, relativistic speed calculation, and 10 energy units.
VSWR Calculator
Calculate VSWR, return loss, reflection coefficient, and mismatch loss. Input from VSWR, impedance, or return loss. Power distribution visual and comprehensive reference table.
Watt Calculator
Calculate electrical power in watts using multiple formulas: P=VI, P=I²R, P=V²/R, P=E/t, or P=τω. Includes energy cost estimation, unit conversions, and power scale comparison.
Watt Converter
Convert between 16 power units: watts, kilowatts, megawatts, horsepower (mechanical, metric, boiler), BTU/hr, dBm, dBW, calories/sec, and more. Log-scale power comparison visual.
Watt-Hours Calculator
Calculate energy in watt-hours from power and time, Ah and voltage, or estimate battery run time and required capacity. Includes DoD, efficiency, cost estimation, and battery comparison visual.
Watts to Amps Calculator
Convert watts to amps for DC, single-phase, and three-phase AC circuits. Includes power factor, NEC breaker sizing, wire gauge recommendation, voltage drop check, and appliance reference table.
Watts to Heat Calculator
Convert electrical power to heat output and calculate temperature rise in materials. Supports air, water, metals, oil. Includes heating rate, time to target temperature, timeline visual, and materi...
Watts to Lux Calculator
Convert electrical watts to illuminance (lux) or calculate watts needed for target lux. Supports 10 light sources, utilization/maintenance factors, lux scale visual, and source comparison table.
Wavelength Calculator
Calculate wavelength from frequency or frequency from wavelength. Supports all EM spectrum bands, refractive index, photon energy, wave number. Includes spectrum visual and reference table.
Wavelength to Frequency Calculator
Convert wavelength to frequency for any EM radiation. Supports pm to km, 8 wavelength units, photon energy, wave number, visible color identification. Includes spectrum visual and conversion tables.
Wire Resistance Calculator
Calculate wire resistance from AWG gauge or diameter, length, material, and temperature. Supports 7 conductor materials, temperature correction, cmil conversion. Includes temp effect visual and AWG...
Wire Size Calculator
Calculate the correct wire gauge (AWG) for any circuit. Factors in ampacity, voltage drop, NEC continuous load rule, conduit fill derating, and insulation rating. Includes NEC ampacity table and de...