The fastest way to get good at electrical exam calculations
CalcReps is a practice site for electricians preparing for journeyman and master licensing exams. Instead of watching someone else solve a voltage drop problem, you solve one yourself, line by line, and the worksheet tells you the moment a number is wrong.
Why videos aren't enough
Most exam prep is hours of video and a thick workbook. You watch an instructor work through a load calculation, it makes sense, and two days later you can't remember whether the dryer goes in at 5,000 VA or nameplate. Calculations are a skill, and skills come from repetition. You need to do dozens of problems, not watch a few.
Practice books help, but they run out of problems and only show the final answer. If you get it wrong, you have to work backward to find out where. CalcReps generates new numbers every time and checks each line, so you find the exact step you're getting wrong and fix it.
How the worksheet works
Every problem opens with a drawing of the job: the run from panel to load, the box with its cables, or the house with its appliance loads. Below it is a worksheet set up like a spreadsheet. Each row is one step of the calculation, with the NEC article you'd look up for it. Type your answer in the cell and press Enter.
Get it right and the row locks in with the work shown. Get it wrong and you see the rule for that step. Miss it twice and you can reveal the answer and keep going. Nothing moves on until the current line is right, which is how bad habits get caught early.
Then practice the way you'll be tested
Licensing exams are multiple choice, timed, and open book. Once a topic feels automatic, switch to the practice exam. It shows one question at a time with four choices, a countdown clock, and a mark-for-review flag, like a computer-based test center. The wrong choices come from real mistakes, so a wrong pick tells you exactly what to fix.
What the Texas exam looks like now
In March 2025 Texas split the journeyman electrician exam into two separately scored parts: NEC knowledge, and calculations. The Calculations part has 26 questions in 110 minutes. Texas licensing data shows that in fiscal year 2025, only about one in five Calculations attempts passed. If you're taking the Texas exam, the math now has to stand on its own.
Other states mix calculations into a single exam, but the topics are the same: voltage drop, box and conduit fill, conductor sizing, motor circuits and dwelling unit load calculations.
What you can practice today
- Voltage drop. Single-phase and three-phase, find the drop or size the conductor for 3%.
- Box fill. Conductors, clamps, devices and grounds under 314.16.
- Dwelling unit load calculations. The full standard method, from general lighting to service amperes.
- Quick practice exam. Five timed multiple-choice questions across all three topics.
Motor circuits, conduit fill, ampacity adjustment and commercial load calculations are coming next, along with a full 26-question timed exam.
Built for the code book you'll use
Every step cites the NEC article or table you'd turn to on test day, so practicing here also trains you to find things in your own code book fast. Problems follow the 2023 NEC.
Common questions
Is CalcReps free?
Yes. Every practice problem and the practice exam are free, with no sign-up.
Which NEC edition do the problems use?
The 2023 NEC. Check which edition your state's exam is based on, since article numbers can change between editions.
Will this help with the Texas journeyman Calculations exam?
That's what it's built for. The practice exam uses the same pace as the Texas Calculations part, about 4 minutes and 14 seconds per question, and covers the most common calculation topics.
Do I need my code book?
It helps. The real exam is open book, and the worksheet cites the article or table for each step so you get used to looking things up quickly.
Does my progress save?
Your progress is saved in your browser on this device. It isn't tied to an account, so it won't carry over to another phone or computer.
Start with one voltage drop problem
It takes about two minutes, and you'll see exactly how the worksheet catches mistakes.
Start practicing for free