# EleCalculator.com

> Free professional electrical calculators for US electricians, engineers, and students. NEC-compliant tools covering 86+ specialized calculations across 16 categories.

## About

EleCalculator.com provides high-precision, NEC-compliant electrical calculation tools. All calculators are free, require no signup, and produce instant results following the National Electrical Code (NEC 2023). The site serves electrical engineers, licensed electricians, contractors, and electrical engineering students.

## Calculator Categories

### Basic Electrical Laws
- [Ohm's Law Calculator](https://elecalculator.com/calculator/basic/ohms-law/): Calculate voltage, current, resistance, and power using Ohm's Law (V=IR, P=VI).
- [Power Calculator](https://elecalculator.com/calculator/basic/power-calculator/): Single-phase and three-phase electrical power calculations (P = VI cos θ).
- [Impedance Calculator](https://elecalculator.com/calculator/basic/impedance-calculator/): AC circuit impedance from resistance and reactance (Z = √(R² + X²)).

### Circuit Analysis
- [Voltage Drop Calculator](https://elecalculator.com/calculator/circuit/voltage-drop/): NEC-compliant voltage drop calculations for copper and aluminum conductors.
- [Series Circuit Calculator](https://elecalculator.com/calculator/circuit/series-circuit/): Analyze series circuit configurations — total resistance, current distribution, power dissipation.
- [Parallel Circuit Calculator](https://elecalculator.com/calculator/circuit/parallel-circuit/): Parallel resistance, current divider, and combined impedance calculations.

### Wire & Cable Sizing
- [Wire Size Calculator](https://elecalculator.com/calculator/wire/wire-size/): Select correct AWG wire size based on current, voltage drop, and NEC 310.15 derating.
- [Ampacity Calculator](https://elecalculator.com/calculator/wire/ampacity-calculator/): NEC Table 310.16 conductor ampacity with temperature and conduit fill derating.
- [Conduit Fill Calculator](https://elecalculator.com/calculator/wire/conduit-fill/): NEC Chapter 9 conduit fill percentage — EMT, IMC, RMC, PVC.

### Motors & Loads
- [Load Calculator](https://elecalculator.com/calculator/motor/load-calculator/): Electrical load calculations for service entrance and feeder sizing.
- [Motor Current Calculator](https://elecalculator.com/calculator/motor/motor-current/): Motor FLA from NEC Table 430.248/430.250, conductor and protection sizing.
- [Motor Starting Current Calculator](https://elecalculator.com/calculator/motor/motor-starting-current/): Inrush current estimation for DOL, star-delta, soft starter, and VFD starting methods.

### Safety & NEC Compliance
- [Short Circuit Calculator](https://elecalculator.com/calculator/safety/short-circuit/): Available fault current calculations for electrical system protection coordination.
- [Breaker Sizing Calculator](https://elecalculator.com/calculator/safety/breaker-sizing/): NEC 240.4/210.20/430.52 circuit breaker sizing with conductor protection verification.
- [Arc Flash Calculator](https://elecalculator.com/calculator/safety/arc-flash/): Incident energy and arc flash boundary calculations per IEEE 1584.
- [Grounding Calculator](https://elecalculator.com/calculator/safety/grounding-calculator/): NEC Article 250 grounding electrode system calculations.

### Power Systems
- [Transformer Calculator](https://elecalculator.com/calculator/power/transformer-calculator/): Transformer sizing, impedance, and voltage regulation calculations.
- [Power Factor Calculator](https://elecalculator.com/calculator/power/power-factor/): Power factor analysis with kW, kVA, kVAR power triangle.
- [Power Factor Correction](https://elecalculator.com/calculator/power/power-factor-correction/): Capacitor bank sizing for power factor improvement.

### Testing & Measurement
- [Insulation Resistance Calculator](https://elecalculator.com/calculator/testing/insulation-resistance/): Temperature-corrected insulation resistance testing with pass/fail criteria.
- [Current Shunt Calculator](https://elecalculator.com/calculator/testing/current-shunt/): Shunt resistor selection for current measurement applications.

### Residential Electrical
- [NEC 220 Demand Factor Calculator](https://elecalculator.com/calculator/residential/nec-220-demand-factor/): NEC Table 220.55 cooking equipment, 220.42 lighting, and 220.44 receptacle demand factors.
- [Electrical Panel Load Calculator](https://elecalculator.com/calculator/residential/electrical-panel-load/): Residential panel load analysis and service sizing.
- [Electrical Service Size Calculator](https://elecalculator.com/calculator/residential/electrical-service-size/): Determine required service entrance capacity per NEC Article 220.

### Renewable Energy
- [Solar Calculator](https://elecalculator.com/calculator/renewable/solar-calculator/): Solar panel system sizing, energy production, and ROI estimation.
- [Battery Capacity Calculator](https://elecalculator.com/calculator/renewable/battery-capacity/): Battery bank sizing for backup and off-grid systems.
- [UPS Backup Time Calculator](https://elecalculator.com/calculator/renewable/ups-backup-time/): UPS runtime estimation based on load and battery capacity.

### Conversion Tools
- [Resistor Color Code Calculator](https://elecalculator.com/calculator/tools/resistor-color-code/): 4-band and 5-band resistor color code decoder.
- [Capacitor Code Calculator](https://elecalculator.com/calculator/tools/capacitor-code/): 3-digit ceramic capacitor code to pF/nF/µF conversion.

## Technical Standards

All calculators reference the following standards:
- NEC (National Electrical Code) 2023 Edition
- IEEE 1584 (Arc Flash)
- NEMA standards for motor and equipment ratings
- NEC Tables 310.16, 430.248, 430.250, 220.55

## Languages

- English (default): https://elecalculator.com/
- Spanish: https://elecalculator.com/es/