Calculators
Each tool states the code table it works from and links to the equivalent calculator under the other standards.
Sizing & Selection
- AWG Wire Size CalculatorConvert between AWG, kcmil and mm², and find the conductor area for a given size.
- Transformer Sizing CalculatorStandard kVA for a connected load, plus primary and secondary full-load current.
- Grounding Conductor Size CalculatorGrounding electrode conductor from 250.66, or equipment grounding conductor from 250.122.
- Wire Size CalculatorMinimum conductor for a load, accounting for distance and drop.
- Cable Size CalculatorMetric · UK & AUMetric cable sizing in mm², by current rating and mV/A/m voltage drop.
Load & Protection
- Ampacity CalculatorCurrent-carrying capacity of a conductor after temperature and bundling derating.
- Breaker Size CalculatorNext standard overcurrent device rating for a continuous or non-continuous load.
- Residential Load CalculatorMinimum service size for a single-family dwelling, by the NEC optional method.
- Motor FLA CalculatorNEC table full-load current for a motor, with the conductor and breaker sizes it drives.
- EV Charger Circuit CalculatorBreaker and wire size for a Level 2 EV charger, with the mandatory 125% factor.
- Heat Pump & HVAC Circuit CalculatorWire and breaker for AC or a heat pump, from nameplate MCA and MOCP under Article 440.
- Voltage Drop CalculatorPercentage drop over a run, and the size that brings it back in.
Installation
- Conduit Fill CalculatorCross-sectional fill percentage against the Chapter 9 Table 1 limits.
- Box Fill CalculatorVolume allowances for conductors, devices, clamps and grounds against a box’s capacity.
- Conduit Bending CalculatorTrade mathOffset, stub-up and saddle marks, with shrink and take-up worked out.
Power Quality & Backup
- Generator Sizing CalculatorStandby powerBackup generator watts for a load list, including the largest motor starting surge.
- Solar Battery Bank CalculatorDC storageDC storage capacity from daily energy use, autonomy, depth of discharge and losses.
- Power Factor Correction CalculatorFacility powerCapacitor bank kVAR to hit a target power factor, and the kVA demand it saves.