Electrical Calculators

Size a dwelling's electrical service/panel from floor area, fixed appliances, and heating/cooling load, per NEC 220.82

Find the required transformer size from your load with a safety margin, rounded to a standard ANSI/IEEE or IEC size, or find full-load current from a known kVA rating

Find the correct generator wattage from your appliances' running and starting watts, with a safety margin applied

Find the solar array size, panel count, and roof area needed to offset your electricity usage

Find your UPS/inverter backup runtime from a battery bank, or size the battery bank for a target runtime

Find the recommended AWG wire gauge from load current, voltage, and run length, checking NEC ampacity and voltage drop

Check voltage drop and receiving-end voltage for a specific wire size, or solve for the maximum run length within your allowed drop

Find the correct standard breaker size per NEC 210.20/240.6, combine multiple loads on one circuit, and check GFCI/AFCI requirements

Find the required conduit trade size for a mixed list of conductors, per NEC Chapter 9

Check whether an outlet, device, or junction box has enough volume for its conductors, clamps, fittings, and equipment grounding conductors, per NEC 314.16

Find the minimum grounding electrode conductor size per NEC Table 250.66, with electrode-type caps for rod/pipe/plate, concrete-encased, and ground ring electrodes applied automatically

Find the minimum equipment grounding conductor size per NEC Table 250.122, from the circuit's OCPD rating and material, with the 250.122(B) proportional increase applied automatically

Find the correct wire size and breaker for your EV charging circuit, per NEC 625.41's 125% continuous-load factor

Find general lighting demand load and the number of branch circuits needed, per NEC Table 220.42/220.45

Find the required wire and breaker size for AC/HVAC equipment per NEC Article 440, from nameplate MCA/MOCP or motor RLA/FLA ratings

Find what your equipment costs to run per day, week, month, and year, from wattage, usage, and your electricity rate