The NEC Electrical Calculator App is built for electricians, apprentices, and inspectors who need fast, dependable calculations based on the National Electrical Code. It replaces manual lookups and handwritten math with clear, code-aligned calculators designed around how electrical work is actually done in the field and on exams. Whether you’re verifying an installation, planning a circuit, or studying for a licensing exam, the app helps you make confident decisions quickly.
CIRCUIT CALCULATIONS
The Circuit Calculations tool helps determine current, voltage, power, resistance, and related electrical values for common AC and DC circuits. It is useful for checking circuit behavior, understanding load relationships, and validating calculations commonly tested on journeyman and master electrician exams. The calculator reflects real electrical relationships, making it practical for both learning and jobsite use.
LOAD CALCULATOR
The Load Calculator helps calculate branch circuit, feeder, and service loads using NEC demand factors and standard load assumptions. It allows users to evaluate whether panels, feeders, and services are properly sized for the connected load. This tool is useful when planning installations, reviewing existing systems, or preparing for load calculation questions.
CONDUIT FILL
The Conduit Fill calculator helps determine the maximum number and size of conductors permitted in a given raceway. It follows NEC conduit fill rules and helps ensure installations comply with allowable fill percentages. This calculator is useful during planning, field verification, and exam preparation.
MOTOR CALCULATIONS
The Motor Calculations tool supports common NEC motor-related calculations, including conductor sizing and overcurrent protection considerations. It helps users work through multi-step motor problems commonly found on licensing exams and in real-world installations.
TRANSFORMER CALCULATIONS
The Transformer Calculations tool helps calculate primary and secondary currents, conductor sizing considerations, and transformer relationships for common single-phase and three-phase systems. It supports scenarios encountered in both exam questions and real installations.
VOLTAGE DROP – MINIMUM CONDUCTOR SIZE
This calculator helps determine the minimum conductor size required to stay within recommended voltage drop limits for a given load, distance, and system configuration. It is useful when designing circuits where performance matters and when solving exam questions.
VOLTAGE DROP – MAXIMUM CIRCUIT DISTANCE
This calculator helps determine the maximum allowable circuit length before exceeding recommended voltage drop limits for a given conductor size and load. It is useful for evaluating long runs to remote equipment.
VOLTAGE DROP PERCENTAGE
The Voltage Drop Percentage calculator allows users to quickly calculate voltage drop as a percentage of system voltage. It helps verify compliance with recommended voltage drop guidelines and understand performance impacts.
COOLING / HEAT PUMP CALCULATIONS
The Cooling and Heat Pump Calculations tool supports electrical calculations related to HVAC equipment commonly found in residential and light commercial work. It helps users evaluate circuit requirements for heating and cooling systems.
RESISTIVE HEATING CALCULATIONS
Resistive Heating Calculations tool supports calculations for electric heating loads, allowing users to determine current, power, and circuit requirements. It is useful for verifying conductor sizing and working through resistive heating scenarios.
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2. feb 2026.