Is Tom Henry good for the California General Electrician exam?

Tom Henry is excellent for the calculation skill, which is the Determination of electrical system requirements domain, about 22% of the California exam. It does not cover the other roughly 78% (Installation, Safety, Maintenance and Repair) or codebook-lookup speed.

Tom Henry or JourneymanIQ for the California exam?

If calculations are your only weak spot and you like hand-drilling, Tom Henry's workbooks are hard to beat. If you need the whole DIR outline covered, a diagnostic to find your weak domains, and provided-reference speed, JourneymanIQ is built for that.

If your diagnostic shows calculations are your worst domain, drilling Tom Henry by hand and then practicing the same patterns on JourneymanIQ is a strong combination. The free diagnostic tells you whether you even need to.

Comparison · California

JourneymanIQ vs Tom Henry for the California General Electrician exam

Tom Henry's calculation workbooks are the gold standard for drilling math by hand. JourneymanIQ covers all four California DIR domains with a free diagnostic and adaptive practice. The question is whether you need calculations sharpened or the whole exam covered.

Last reviewed June 2026

Side by side for the California exam

Feature	JourneymanIQ	Tom Henry
Covers all four DIR domains		Calculations focus
Free diagnostic of your weak domains
Hand-calculation drilling depth	Strong, with step reveal	The gold standard
Scaffolded lessons (watch, do with help, drill)		Workbook practice
Adapts to the calc types you keep missing
Trains provided-reference lookup speed		Calc-focused
Format	Adaptive app, mobile	Print workbooks
Price	$49/mo or $129/3mo	Roughly $50 to $150 in books

Tom Henry owns hand-calculation drilling. JourneymanIQ covers the full exam and points you at the right work with a diagnostic.

What Tom Henry does well

The deepest hand-calculation drilling available, built over decades.
Step-by-step worked examples for the math that fails most candidates.
Best when calculations are your one clear weak spot and you like working problems on paper.

Where Tom Henry leaves gaps for California

Calculations are only about 22% of the California exam. Installation alone is 66%.
No coverage of codebook-lookup speed, which decides the exam when references are provided at the test center.
No diagnostic, so you do not know if calculations are even your worst domain.
Print workbooks, not adaptive practice that resurfaces what you keep missing.

What JourneymanIQ does well for California

A free diagnostic that shows whether calculations, Installation, or codebook speed is actually costing you points.
Scaffolded calculation lessons: watch one worked, run one with help, then drill it cold.
Show-the-work calculators that build the math one step at a time, so you learn the pattern.
Coverage of all four DIR domains, not just the math.

When to pick which

Pick Tom Henry if

You already know calculations are your weak spot.
You learn math best by working problems on paper.
You only need the calculation portion sharpened.

Pick JourneymanIQ if

You are not sure which DIR domain is costing you the most points.
You need the whole exam covered, not just calculations.
You want adaptive practice and provided-reference speed work in a 30 to 60 day window.

The bottom line

Tom Henry is the best calculation drilling there is. The California exam is bigger than calculations. Run the free diagnostic first. If it says math is your worst domain, drill Tom Henry and reinforce on JourneymanIQ. If it says Installation or codebook speed is the problem, that is where your time should go instead.

What you actually get

This isn’t another article. It’s the prep system.

Free diagnostic

15 questions, no signup. A domain-by-domain weakness map for the DIR General Electrician exam, so you study the gaps, not everything.

Take it free

Show-the-work calculators

Voltage drop, conduit fill, box fill, dwelling load. The math builds one step at a time, so you learn the pattern, not just the answer. Free, no login.

Open the calculators

Scaffolded lessons

Watch one worked, run one with help, then drill it cold. Every calculation type the exam tests, in plain language.

See the lessons

Drills that adapt

Original California questions and code-navigation drills. The platform resurfaces the calculation types you keep missing until they stick.

See plans

Find your path

If you failed it onceThe 60-day wait is the work window. Find your two weakest domains and attack those, not a re-read of what you already knew.Build a retake plan If you’re still checking the rulesWhat’s provided at the test center, the 8,000 hours, C-10 vs General Electrician. Get the current facts before you study the wrong thing.Check the requirements If codebook speed is the weak spotReferences are provided, so the exam rewards whoever finds the rule fastest. Train the lookup, not just the rule.Train codebook speed

Start here

See exactly where you stand on the California exam.

15 questions, about 15 minutes, no signup. You get a domain-by-domain weakness map for the DIR General Electrician exam, so you study the gaps instead of everything.

Take the free diagnostic