Free web tools
Free NEC calculators for electricians
Don't take our word for it. Run one. The same verified NEC engines that power the JobVolt app, free in the browser. No install, no account. Type your numbers and watch the work appear.
- Table 310.16
Wire Size Calculator
Conductor size with deratingOpen - Ch. 9 Table 8
Voltage Drop Calculator
Size for a long runOpen - Ch. 9 Tables 1, 4, 5
Conduit Fill Calculator
Raceway fill checkOpen - 314.16
Box Fill Calculator
Box volume checkOpen - V = I·R
Ohm's Law Calculator
V, I, R and powerOpen - 220.82
Load Calc
Dwelling service sizeIn the app · Pro - Art 430
Motor
FLC, OCPD, overloadIn the app · Pro - Art 250
Grounding
EGC and GEC sizingIn the app · Pro
The app does what a browser can't.
Offline in the crawlspace, every calculation saved to History, and inspector-ready PDF submittals on your company letterhead. Same engines, same citations.
