Free Electrician Tools
NEC-based calculators and reference guides for study and field reference. No account required.
Eleven calculators covering selected NEC calculation methods: 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 educational example. Confirm the permitted tools, references, and requirements for any particular examination with current official instructions.
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
State information resources with guidance to confirm current licensing requirements, fees, and reciprocity with the responsible authority.
Electrician Salary by State
Salary information is under primary-source review.
NEC Quick Reference
Printable NEC study reference covering conductor sizing, GFCI/AFCI rules, box fill limits, and more.
Free NEC Study Guide
A 20-page PDF covering selected NEC study topics. Confirm your examination's current official content outline for applicable subjects.
Study page held for review
This page is withheld. Code figures, exam rules, and licensing details are not shown until each claim is checked.
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 calculators use 2023 NEC references. Confirm the current code edition, exam scope, and permitted references in the official information for your examination.
Can I use a calculator on the licensing exam?
These browser tools are for study and reference. Calculator and electronic-device rules vary by exam, so check the current official candidate bulletin before selecting an allowed calculator.
Are these accurate enough to use on the job?
Each page identifies the NEC articles and tables used by the calculation. Use these tools as a study and reference aid, then verify the result against the applicable code edition, project requirements, and authority having jurisdiction.
Which calculations show up most on the exam?
The calculations assessed depend on the jurisdiction's current exam outline. Use official materials to identify relevant subjects.
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