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ELECTRICAL APPRENTICE · MATH PRACTICE

Electrician math practice and printable worksheet

Build confidence with five worked electrical math examples, then print a free 12-question worksheet and separate answer key. Practice volts, amps, ohms, power and percentages before a timed exam.

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Electrician math practice and printable worksheet

Five electrician math problems worth knowing cold

You don't have to love mathematics to become good at electrical calculations. The useful habit is to choose the right relationship, keep the units straight and verify the result. Work these short examples before revealing the answers.

01 · OHM'S LAW A 120-volt circuit has 20 ohms of resistance. What current flows?
Answer: 6 A.

Ohm's law: I = V ÷ R = 120 ÷ 20 = 6 amperes. This is a simple idealized resistive example.

02 · POWER A 240-volt single-phase load draws 12 amperes. What is its apparent power?
Answer: 2,880 VA.

Apparent power = V × A = 240 × 12 = 2,880 volt-amperes, or 2.88 kVA. Watts equal VA only at unity power factor.

03 · SERIES RESISTANCE What is the total resistance of 8 Ω and 12 Ω in series?
Answer: 20 Ω.

Series resistances add directly: 8 + 12 = 20 ohms.

04 · PARALLEL RESISTANCE Two 12 Ω resistors are connected in parallel. What is the equivalent resistance?
Answer: 6 Ω.

For two equal resistors in parallel, equivalent resistance is half of one: 12 ÷ 2 = 6 ohms.

05 · VOLTAGE PERCENTAGE What is 3% of a 120-volt nominal voltage?
Answer: 3.6 V.

120 × 0.03 = 3.6 volts. This computes a percentage; it does not establish whether a particular wiring installation meets a Code requirement.

How to study electrical math without memorizing a hundred answers

  1. Write the known values with units. Volts, amps, ohms, watts and volt-amperes are not interchangeable.
  2. Pick a formula based on the question. For example, use I = V ÷ R for an ideal resistive relationship; use VA = V × A for basic single-phase apparent power.
  3. Show one line of work. Even a simple setup helps you spot arithmetic errors under pressure.
  4. Check that the result makes sense. Higher resistance at constant voltage should produce lower current.
  5. Separate formulas from Code sizing. Conductor, overcurrent and service questions need the appropriate NEC sections and conditions, not just algebra.

Next step: practice under exam conditions

Our free 12-question diagnostic covers electrical math, concepts and Code-navigation thinking. When you're ready for structured training, Electrical Apprentice Pro combines short study sessions with practice, feedback and review. Need advanced multi-step work? See Master-level calculation practice. For NEC lookup practice, see how to study the NEC and the 2023 versus 2026 Code-edition comparison. To explore the available study tools first, see the seven-day no-card TRADECAIRN Pro Pack trial.

Behind TRADECAIRN

Built from more than 20 years in the electrical trade.

TRADECAIRN was founded by Zach Jerry, whose electrical background includes Master Electrician and electrical contractor licenses held in multiple states and multiple trade and safety training credentials. Meet the founder and see our technical standards →

TRADECAIRN is independent exam preparation, not an ICC, NFPA, state licensing authority, or testing-provider product. Content cannot replace official exam instructions or the adopted code.

Frequently asked questions

Do I have to be good at advanced math to start electrical training?

You need solid arithmetic, algebra habits and careful use of units. Start with fundamental relationships and build toward the calculations required by your training or exam.

Is this an official licensing exam?

No. These are original educational practice problems, not copied questions from an official electrical licensing examination.

Where can I take a larger free test?

TRADECAIRN offers a separate free 12-question electrician readiness diagnostic covering math, fundamentals and Code-navigation habits.

Explore related study resources

Electrical Apprentice ProStructured apprentice study, code navigation and review.Explore →Electrical apprentice formulasReference common equations and electrical units.Explore →Advanced load calculationsWork through single- and three-phase examples.Explore →

Free printable practice

Electrician math worksheet: 12 original problems

Practice Ohm's law, single-phase and balanced three-phase power, series and parallel resistance, percentages, and unit conversions. Work the problems first, then print or review the separate answer key.

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TRADECAIRN | Electrician Math Practice Worksheet

Name: ____________________________ Date: ___________________ | 12 questions

Show formulas, units and calculation steps. Assume the stated ideal or balanced conditions; round the three-phase result to 0.1 kVA.

  1. Ohm’s law: Find current when an ideal resistive load has 120 V across 24 Ω.

  2. Ohm’s law: Find voltage for an 8 A current through a 15 Ω resistor.

  3. Single-phase apparent power: A load draws 12 A at 240 V. Find VA.

  4. Unity power factor: A 120 V load draws 10 A at PF = 1. Find watts.

  5. Series circuit: Three resistors are 6 Ω, 9 Ω and 15 Ω. Find total resistance.

  6. Parallel circuit: Three equal 18 Ω resistors are in parallel. Find equivalent resistance.

  7. Parallel circuit: A 10 Ω and a 15 Ω resistor are connected in parallel. Find equivalent resistance.

  8. Power factor: A single-phase load draws 5 A at 120 V with PF = 0.80. Find real power.

  9. Balanced three-phase system: Line voltage is 480 V and line current is 20 A. Find apparent power, rounded to 0.1 kVA.

  10. Percentage arithmetic: What is 3% of 240 V?

  11. Unit conversion: Convert 2.5 kW to watts.

  12. Ideal unity-power-factor resistive load: A 600 W load operates at 120 V. Find current.

Independent educational practice, not an electrical installation design, safety procedure, NEC interpretation, or an official licensing examination. Check all actual work against current requirements and qualified supervision.

Review all 12 answers and worked solutions

TRADECAIRN | Electrician Math Worksheet — Answer Key

Answers correspond to the 12 questions above. Check the relationship, calculation and units—not just the final number.

  1. 5 A

    I = V ÷ R = 120 ÷ 24 = 5 A.

  2. 120 V

    V = I × R = 8 × 15 = 120 V.

  3. 2,880 VA

    S = V × I = 240 × 12 = 2,880 VA (2.88 kVA).

  4. 1,200 W

    P = V × I × PF = 120 × 10 × 1 = 1,200 W.

  5. 30 Ω

    R total = 6 + 9 + 15 = 30 Ω.

  6. 6 Ω

    For n equal parallel resistors: R equivalent = 18 ÷ 3 = 6 Ω.

  7. 6 Ω

    R = (10 × 15) ÷ (10 + 15) = 150 ÷ 25 = 6 Ω.

  8. 480 W

    P = V × I × PF = 120 × 5 × 0.80 = 480 W.

  9. 16.6 kVA

    S = √3 × V line × I line = 1.732 × 480 × 20 ≈ 16,627 VA = 16.6 kVA.

  10. 7.2 V

    240 × 0.03 = 7.2 V. This is arithmetic, not a Code compliance assessment.

  11. 2,500 W

    2.5 kW × 1,000 = 2,500 W.

  12. 5 A

    I = P ÷ (V × PF) = 600 ÷ (120 × 1) = 5 A.

Educational arithmetic examples only. Actual Code sizing and safety decisions require the governing edition, installation facts and applicable authority.

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Follow a study plan that combines NEC navigation, electrical calculations, practice questions, and state-specific licensing research.

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