Free Electrician Tools
NEC-based calculators and reference guides to help you on the job and on the exam. No account required.
Eleven calculators covering the NEC math that shows up on journeyman and master licensing exams and on the job: conductor ampacity and derating, box and conduit fill, dwelling load calculations by both the standard and optional methods, motor and transformer sizing, grounding and bonding conductor sizing, voltage drop, and conduit bending.
Every one of them shows its work. Each page lists the exact articles and tables the calculation comes from, walks the method step by step, and includes a worked example in the style the exam asks it. That is deliberate. A number you cannot trace back to a code section is worth nothing to you in a testing center, where the calculator on the desk is a four function model and the answer has to come out of the book.
All values follow the 2023 NEC. Free, no sign up, nothing stored.
Calculators
Dwelling Service Load Calculator
NewSize a dwelling unit service per NEC 220.82 optional method. 100% of first 10 kVA, 40% of remainder, plus the larger of heat or A/C. Suggests standard service size.
Standard Dwelling Load Calculator
NewNEC 220 Part III standard method: general lighting demand factors (220.42), range (220.55), dryer (220.54), and fastened appliances (220.53). Suggests service size.
Motor Circuit Calculator
NewSize 3-phase motor branch circuit conductors and OCPD per NEC 430.22 and 430.52. Full-load current from Table 430.250, OCPD from Table 430.52.
Transformer Sizing Calculator
NewConvert kVA to primary and secondary amps and size OCPD per NEC 450.3(B). Single or three-phase, primary-only or primary plus secondary protection.
Ground Wire Size Calculator
NewSize the equipment grounding conductor by breaker rating (NEC Table 250.122) and the grounding electrode conductor by service size (Table 250.66), in copper or aluminum.
Conduit Bending Calculator
NewOffset multipliers, 3-bend saddle, and 90-degree stub-up take-up. Exact distance between bends, shrink, and back-of-bend marks for EMT.
Ampacity Derating Calculator
NewApply NEC 310.15(B) ambient temperature correction and 310.15(C)(1) bundling adjustment factors to a Table 310.16 base ampacity, step by step.
Voltage Drop Calculator
Calculate voltage drop for any circuit. Copper or aluminum, single or three-phase. See if your run meets the NEC 3% / 5% recommendations.
NEC Box Fill Calculator
Calculate box fill per NEC 314.16 with all 5 counting rules. Conductors, clamps, devices, EGCs, step-by-step volume breakdown.
NEC Conduit Fill Calculator
Check conduit fill per NEC Chapter 9 Tables 1, 4 & 5. Supports EMT, IMC, RMC, PVC with THHN, XHHW-2, THW, and RHH wire types.
Wire Ampacity Calculator
Look up ampacity per NEC Table 310.16 with temperature correction and conduit fill adjustment factors applied automatically.
Guides & Reference
Compare States
Side-by-side comparison of journeyman and master electrician license requirements, exam fees, and reciprocity for all 50 states.
Electrician Salary by State
Current BLS salary data for electricians broken down by state: hourly rates, annual pay, and top-paying metro areas.
NEC Quick Reference
Printable cheat sheet of the most-tested NEC articles: conductor sizing, GFCI/AFCI rules, box fill limits, and more.
Free NEC Study Guide
A 20-page PDF covering the NEC articles most likely to appear on your journeyman or master electrician exam.
Exam Math Guide
Step-by-step walkthrough of every calculation type that shows up on electrician licensing exams: load calcs, voltage drop, conduit fill.
Questions About These Tools
Are these calculators free?
Yes, all eleven are free with no account required. They run entirely in your browser and nothing is stored. They are built as a way for electricians to find GetLicenseReady, so we would rather they be genuinely useful than gated.
Which NEC edition do they follow?
The 2023 NEC. Table values, article numbers, and section references throughout come from the 2023 edition. If your jurisdiction still tests an earlier edition, the method is the same but a small number of table values and section numbers differ. Check your state page for the edition your exam actually references.
Can I use a calculator on the licensing exam?
Not this one. Most states allow a basic or scientific calculator with no programmable memory and no internet connection, and none allow a phone. These tools are for building speed and checking your work while you study, so that on exam day you can do the same calculation from the code book.
Are these accurate enough to use on the job?
They implement the NEC methods correctly and each page shows the exact articles and tables used, so you can verify any result against your own code book. They are a check on your work, not a substitute for it. The authority having jurisdiction and the code edition adopted where you work always govern.
Which calculations show up most on the exam?
Conductor ampacity with correction and adjustment factors, box fill, conduit fill, dwelling load calculations, and grounding conductor sizing account for the large majority of calculation questions on journeyman exams. Motor and transformer sizing weigh more heavily on master exams.
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