One App Instead of a Drawer: The Offline Electrician Calculator
Open the App Store, search "conduit bending," and you'll find five different paid apps that each do exactly one thing — and look like they were built in 2014. Search "voltage drop," "box fill," "ampacity," and it's the same story. Most working electricians end up paying for a whole drawer of single-trick tools.
The problem isn't the math — it's the friction
Every one of these calculators is the same handful of NEC formulas. What's missing is a single tool that's fast on the job: big tap targets you can hit with gloves on, results that read instantly in bad light, and — critically — one that works with no signal, because the panel you're standing in front of is in a basement or a mechanical room.
What "all of it" actually means
A complete field calculator covers:
- Voltage drop — % drop and conductor sizing (the 3% rule)
- Wire ampacity — NEC 310.16 by size or by load, with the standard breaker
- Conduit fill — Chapter 9, Table 1 (53% / 31% / 40%)
- Box fill — 314.16 cubic-inch capacity
- Conduit bending — offset, saddle, 90° stub-up
- Ohm's law / power wheel — any two of V, I, R, P
- Motor FLC — full-load amps, 125% conductor, 250% OCPD
- Converters — A·W·VA·kVA and AWG ↔ mm² ↔ cmil
…plus the reference tables you actually look up: ampacity, wire colors, fill percentages.
Trust comes from showing the work
The difference between a calculator you trust and one you double-check is whether it tells you where the number came from. Voltly prints the formula and the NEC article on every result, and a standing reminder to verify against your adopted code. It's a quality instrument, not a black box.
Two calculators (voltage drop and Ohm's law) are free forever. The rest unlock once for $9.99 — no subscription, fully offline.
Voltly is a field aid for licensed electrical work, not a substitute for the NEC or engineering judgment.