VD = 2·K·I·L ÷ CM 40% fill 20 BTU / sq ft USE IT · DRILL IT · ASK IT OUT LOUD
Free Job-Site Tools

The Talking Toolbox

Real job-site tools you can use, drill, or simply ask out loud. Free forever. Works with gloves on.

Working calculators for voltage drop, conduit fill, and BTU sizing — on any phone, no login. Flip any tool into Drill Mode and it quizzes you with endless job-site problems. Or keep your hands on the ladder and just ask GENO: "Thirty amps, copper, ninety feet, two-forty volts." He knows the tables, he's memorized the book, and he answers out loud in 83 languages.

A free EPA 608 practice exam with a printable readiness certificate rounds out the bench — and every tool traces back to Job-Site Math, the field companion behind it all.

Open the Toolbox Free EPA 608 Practice Exam
The GSU Tool Bench

Real Job-Site Tools. Free Forever.

Working calculators built for the field — the same math a journeyman runs in his head, on your phone, with no login and no paywall. Use them on the job today; ask GENO to explain the math behind them, out loud, any hour of the night.

Electrical

Voltage Drop Calculator

Single- and three-phase, copper and aluminum, 14 AWG to 500 kcmil. Instant percent drop, pass/fail against the NEC 3% recommendation, and the smallest wire that passes.

Open the Tool → Electrical

Conduit Fill Calculator

THHN in EMT or PVC Schedule 40, mixed sizes welcome, checked against the NEC Chapter 9 fill limits. Names the smallest conduit that legally fits your pull.

Open the Tool → HVAC

BTU Sizing Calculator

Size a window unit or mini-split like a tech: floor area, ceilings, sun, insulation, occupants, kitchen heat, climate. BTU/hr and tonnage in one glance.

Open the Tool → HVAC · Certification

Free EPA 608 Practice Exam

40 original questions across Core, Type I, II & III, graded against the real exam's 70%-per-section bar, with explanations and a printable readiness certificate.

Take the Exam →
Free forever. Works on any phone. No login. More tools joining the bench: pipe slope & fall, stair rise-and-run, concrete yardage, board-foot lumber.
Job-Site Math book cover
The Book Behind the Bench

Job-Site Math: The Sovereign Tradesman's Field Companion

Every calculator on this bench is a chapter in this book — worked examples, practice problems, a full answer key, and a Tradesman's Dictionary. GENO has memorized the entire book and will teach it to you out loud.

Get It on Kindle — $3.99 More from Dr. Constant
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