Calculator Library
Electrical calculators
125 professional tools covering design, safety, and troubleshooting.
- Total calculators
- 125
- Categories
- 16
- Focus
- US field and design work
Start with basic laws, then move into circuits, wire sizing, motors, and safety. Each calculator group is organized by real electrical tasks rather than formulas only.
Popular calculators
Direct links to core tools for voltage, wire size, load, and motor current checks.
Basic Electrical Laws
First-principles voltage, current, resistance, power, and energy calculators for foundational electrical checks.
Ohm's Law Calculator
Calculate voltage, current, resistance, and power using Ohm's Law and power formulas
Power Calculator
Electrical power calculator for DC, single-phase AC, and balanced three-phase AC relationships between voltage, current, real power, apparent power, reactive power, and power factor.
Voltage Calculator
Compute circuit voltage for DC and AC resistive loads from current, resistance, or power using standard Ohm's Law relationships (V = I × R, V = P / I, V = √(P × R)).
Current Calculator
Calculate current, voltage, resistance, and power using core Ohm's Law relationships, optimized for current-focused workflows.
Energy Calculator
Calculate energy consumption, costs, savings, and efficiency comparisons for electrical equipment and solar systems
Impedance Calculator
Circuit impedance calculator for series and parallel RLC networks, complex impedance magnitude and angle, and a basic series-resonance screen.
NEC Code Compliance
NEC 314 box-fill and pull-box sizing checks for U.S. rough-in and installation planning
Pull Box Sizing Calculator
Screen straight, angle, and U-pull box dimensions from NEC 314.28 using governing raceway rows and the trade size of the largest raceway.
Box Fill Calculator
Calculate electrical box fill requirements per NEC 314.16. Determine if your outlet box, junction box, or switch box has sufficient volume for conductors, devices, and fittings.
Conduit Bending
Field layout tools for offsets, kicks, saddles, segmented bends, and concentric conduit spacing
Offset Bend Calculator
Field-chart geometry screen for equal-angle conduit offsets. Returns bend spacing, shrinkage allowance, travel, and optional first and second bend marks.
Kick Bend Calculator
Calculate kick bend (90° with offset) for transitioning conduit from wall surface to electrical panels, junction boxes, or equipment. Supports both trigonometric and field multiplier methods.
Saddle Bend Calculator
Calculate 3-point and 4-point saddle bend marks for routing conduit over obstacles. Outputs mark locations, bend spacing, and shrinkage for common field angles.
Segment Bend Calculator
Geometry screen for equal-angle segmented conduit bends. Returns bend angle, smooth-arc reference spacing, straight chord step, and optional bend-mark stations from a first-mark reference.
Parallel Roll Offset Calculator
Calculate rolling offsets for conduit that must move both horizontally and vertically. Provides true offset, roll angle, mark spacing, and shrinkage compensation.
Concentric Bend Spacing Calculator
Calculate spacing and mark adjustments for parallel conduit runs on bends. Ensures consistent appearance with proper radius and developed length calculations for each conduit.
Circuit Analysis
Voltage-drop, divider, RC, and resistor-network calculators for branch-level circuit review.
Circuit Analysis Calculator
Analyze one-source DC resistive, AC series RLC, and AC parallel RLC operating points without pretending to be a full circuit simulator.
Voltage Drop Calculator
Calculate voltage drop in electrical conductors for single and three-phase systems
Voltage Divider Calculator
Calculate voltage division in resistor circuits for circuit design and signal conditioning
Current Divider Calculator
Calculate branch current, equivalent resistance, network voltage, and resistor power for 2 to 6 parallel resistive branches.
Series Circuit Calculator
Calculate series resistance, voltage drops, current, and power for resistors connected in series
Parallel Circuit Calculator
Calculate parallel resistance, current distribution, and power for resistors connected in parallel
Wire & Cable
Conductor sizing, ampacity, raceway fill, and installation-limit calculators for U.S. wire and cable work.
Wire Size Calculator
Calculate NEC-style wire sizes from load current, ampacity basis, and voltage-drop targets
Wire Gauge Converter
Convert between AWG, metric (mm²), SWG, and diameter measurements
Wire Ampacity Calculator
Calculate conductor ampacity with temperature correction, conductor-count adjustment, and 60°C or 75°C termination checks
Temperature Correction Calculator
Screen conductor ampacity derating from ambient temperature, more than three current-carrying conductors, and the governing equipment termination limit.
Cable Ampacity Calculator
Calculate cable current carrying capacity with temperature and bundling corrections per NEC
Conduit Fill Calculator
Calculate conduit fill percentages, maximum wire counts, and conduit sizing per NEC requirements
Motors & Loads
Motor load, starting, protection, and cable-screening calculators for rotating equipment review.
Electrical Load Calculator
Estimate demand load, service current, and a recommended U.S. service size for dwellings and preliminary non-dwelling projects.
Motor Current Calculator
Compare NEC table full-load current with formula current, screen starting current, and check preliminary AC motor branch-circuit sizing.
Full Load Current Calculator
NEC Table 430.248/430.250 motor full load current (FLC) lookup with conductor sizing, overload-basis reminder, and branch-circuit breaker requirements
Motor Power Calculator
Calculate motor electrical and mechanical power, efficiency, and perform power unit conversions
Motor Efficiency Calculator
Screen one motor operating point from shaft output and either measured input power, one efficiency value, or a simple two-efficiency comparison.
Motor Starter Calculator
Screen NEMA starter size, controller current class, overload-relay setting range, and basic control-package notes for common U.S. motor starters.
Power Systems
Transformer, power-factor, harmonics, generator, and distribution-screening calculators for U.S. power systems.
Transformer Calculator
Screen transformer kVA, turns ratio, full-load current, operating-point losses, and secondary-terminal fault current from basic nameplate inputs.
Power Factor Calculator
Calculate power factor, reactive power requirements, and capacitor sizing for power factor correction
Power Factor Correction Calculator
Screen capacitor kvar, apparent power reduction, and line-current reduction for balanced three-phase power-factor correction work.
Power Factor Penalty Calculator
Calculate utility power factor penalties, correction savings, and optimal capacitor sizing for industrial facilities
Power Quality Calculator
Analyze voltage variations, frequency deviations, harmonic distortion, and power quality compliance
Harmonic Analysis Calculator
Calculate power system harmonics, THD analysis, and power quality assessment
Lighting Design
Lumen, illuminance, emergency-lighting, and circuit-load calculators for preliminary lighting design review.
Lumen Calculator
Lumen calculator for watts-to-lumens, lumens-to-watts, lm/W efficacy, and simple room-lumen requirements.
Lighting Design Calculator
Preliminary lumen-method calculator for room lighting in feet, footcandles, lumens, and fixture count.
Lighting Circuit Calculator
Calculate lighting loads, circuit design, and energy efficiency for optimal illumination
LED Power Calculator
Calculate LED lighting power consumption, energy savings, and replacement analysis
Color Temperature Calculator
Calculate color temperature, CRI, and lighting quality for various applications and circadian lighting
Emergency Lighting Calculator
Size emergency and exit lighting battery backup systems. Calculate required battery capacity per NEC 700 and NFPA 101 Life Safety Code.
Safety & Protection
Breaker, fault-current, grounding, arc-flash, and protection screening for U.S. electrical work
Arc Flash Calculator
Scale incident energy, arc flash boundary, and minimum arc rating from a known base incident-energy case.
Electrical Safety Calculator
Professional electrical safety analysis per NFPA 70E and OSHA standards
IEEE 1584 Arc Flash Calculator
Review core IEEE 1584 scope, screened task-distance incident energy, and boundary position from a published study case.
Short Circuit Current Calculator
Estimate available fault current from transformer impedance, feeder impedance, or known source impedance.
Circuit Breaker Sizing Calculator
Calculate standard breaker sizes for general loads, continuous loads, and simplified motor branch-circuit reviews
Fuse Sizing Calculator
Screen general branch-load, motor branch-fuse, transformer primary-fuse, and capacitor-bank fuse ampere ratings from a visible current basis.
Testing & Measurement
Insulation, grounding, cable, relay, and measurement calculators for documented electrical testing workflows.
Insulation Resistance Calculator
Correct megger readings for temperature, apply a rotating-machine rule-of-thumb screen at 40°C, or compare two readings at the same reference temperature.
Electrical Testing Calculator
Screen insulation resistance, 62% fall-of-potential setup, contact resistance drift, and tan-delta trend movement without pretending to replace manufacturer or NETA acceptance criteria.
Cable Testing Calculator
Calculate cable fault location and testing parameters for insulation, hi-pot, and fault analysis
Load Testing Calculator
Calculate electrical load testing parameters for generators, UPS, batteries, and other equipment
Relay Testing Calculator
Calculate relay settings and test parameters for protection system testing per IEEE standards
Current Shunt Calculator
Size DC current shunts from target millivolt drop, derive ammeter shunts from meter-movement data, or check the voltage drop and power loss of an existing shunt.
Cost & Energy
Electricity cost, appliance energy, savings, and ROI screening for U.S. electrical planning
Electricity Cost Calculator
Estimate electricity cost from load power, operating hours, billing days, and your utility rate.
Energy Savings ROI Calculator
Calculate return on investment for energy efficiency projects and upgrades
Appliance Energy Calculator
Calculate energy consumption, operating costs, and efficiency for household appliances
Appliance Power Consumption Calculator
Calculate power consumption and electricity costs for household appliances
VFD Energy Savings Calculator
Calculate variable frequency drive energy savings and ROI
Electrical Cost Analysis Calculator
Screen electrical project cost, energy cost, simple ROI, and lifecycle cost from user-entered assumptions.
Conversion Tools
Unit conversion, component-marking, and reference tools for AWG checks, resistor and capacitor codes, temperature drift, and bench troubleshooting.
Resistor Color Code Calculator
Decode resistor values from color bands for 4, 5, and 6 band resistors
Capacitor Code Calculator
Decode common capacitor marking codes, convert values to standard markings, and review tolerance context
Temperature Converter
Convert absolute temperatures and temperature differences between Celsius, Fahrenheit, Kelvin, and Rankine for electrical and thermal reference work.
Electrical Unit Converter
Convert between different electrical units including voltage, current, power, energy, and more
Decibel Calculator
Convert power, voltage, sound pressure, and gain values to and from decibels
Temperature Coefficient Calculator
TCR calculator for linear ppm/°C drift checks on resistance, capacitance, inductance, voltage references, and frequency.
Renewable Energy
Solar, battery, inverter, UPS, EV charging, and wind screening calculators for U.S. distributed-energy and backup-power planning.
Solar Calculator
Calculate solar panel energy production, cost savings, and payback period for residential solar installations
Solar ROI Calculator
Calculate solar payback, export-credit value, user-entered incentives, degradation, and cash-flow assumptions
Solar System Design Calculator
Calculate PV array size, panel count, first-year production, degradation, and roof-area fit from monthly electricity use
Solar Row Spacing Calculator
Screen PV row pitch, inter-row shadow length, and ground coverage ratio from latitude, solar altitude, tilt, and module geometry.
Solar Combiner Sizing Calculator
Screen PV source-circuit current, string OCPD review points, combiner output current, and inverter input-current warnings from module Isc and parallel strings.
Wind Power Calculator
Preliminary wind turbine screen for operating-point output, annual energy, and resource class assumptions.
Residential Electrical
Dwelling load, panel, branch-circuit, and service-sizing calculators for U.S. residential electrical planning.
Residential Load Calculator
Screen common U.S. dwelling service-load demand, service current, and a practical next service size.
Branch Circuit Count Calculator
Screen the number of dwelling-unit branch circuits to plan from floor area, required 20A dwelling circuits, and user-entered dedicated equipment circuits.
Electrical Panel Load Calculator
Screen panel current, utilization, and spare capacity for common U.S. residential and light-commercial panels.
Home Circuit Calculator
Calculate residential electrical circuits, loads, and wire sizing per NEC requirements
Outlet Circuit Calculator
Calculate residential outlet circuits and load distribution for NEC compliance
Electrical Service Size Calculator
Screen dwelling-service ampacity from floor area, major electric loads, and a dwelling-style demand method with optional existing-service comparison.
Business & Contracting
Quote, ROI, billing-rate, and project-planning calculators for U.S. electrical contractors.
Electrical Engineering Quote Calculator
Calculate project costs and generate professional electrical engineering quotes
Project Management Calculator
Calculate project timelines, resource requirements, labor costs, and scheduling for electrical projects
ROI Calculator
Calculate return on investment for electrical projects, energy efficiency upgrades, and equipment purchases
Business Planning Calculator
Financial planning tools for electrical contractors including pricing, break-even, and profitability analysis
Components & Devices
Capacitor, inductor, and related component-value calculators for part-level electrical screening.