NEC Calculators
Five field tools that show the intermediate values: base lookup, correction factors, termination caps, voltage drop, fill percentage, breaker limits and the rule that governed the result.
Tools
Start with the question in front of you, then follow the result panel to the next check.
310.16Wire Size & Ampacity CalculatorSize a conductor from load, distance and voltage, with ambient temperature and conductor-bundling corrections applied and shown.Chapter 9 Table 1Conduit Fill Calculator for Multiple Wire SizesMix conductor sizes and insulation types in one raceway, get a pass or fail against the 40 percent limit, and see the cross-section drawn to scale.210.19(A) INVoltage Drop CalculatorSingle-phase and three-phase drop over distance, checked against the three and five percent recommendations.220.82Residential Load Calculation (NEC 220.82)Optional-method service sizing from floor area, appliances, heating and cooling and EV charging, itemised line by line with every demand factor shown.240.4Breaker & Wire Size Compatibility CheckerA pass or fail check on a breaker, conductor and load combination, with the specific rule that decided it.
Typical Workflow
A field calculation usually needs more than one answer.
- Calculate the load.
- Size the conductor.
- Check voltage drop.
- Check conduit fill.
- Confirm breaker compatibility.