Free electrician calculators & NEC tools
The same NEC calculations the journeyman exam tests — free, with every step shown and the exact code references. Built by the team behind the Pass Your Electrician Exam study system.
Conduit Fill Calculator
Fill % against the NEC 53/31/40% limits — wire size, conductor count, EMT size, worked steps.
NEC Chapter 9, Tables 1, 4 & 5
Open calculatorVoltage Drop Calculator
Single- or three-phase voltage drop with the circular-mils formula, checked against the 3% recommendation.
NEC Chapter 9, Table 8 · 210.19(A)
Open calculatorBox Fill Calculator
Required box volume from conductors, devices, and clamps — with the smallest compliant box.
NEC 314.16(B)
Open calculatorWire Ampacity Calculator
Allowable ampacity from Table 310.16 with the 310.15(C)(1) adjustment for >3 conductors applied.
NEC Table 310.16 · 310.15(C)(1)
Open calculatorDwelling Load Calculator
Residential general-load demand by the Article 220 standard method — lighting, small-appliance, laundry.
NEC Article 220
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