Every common electrical, plumbing, and carpentry calc โ cited to NEC, IPC, and IRC code. Not a black box. Works with no signal in the basement.
Most calculators hand you a gauge and stop. Toolbelt keeps going: it derates for ambient heat and conductor bundling, checks voltage drop over the real run length, then prices every candidate gauge so you can see the cheapest one that still passes. On a long pull, that's real money you don't waste on copper.
NEC 310.16, 240.4(D), IPC 703.2 โ printed right on the answer, so you can show the inspector where it came from.
Ambient temperature correction, conductor bundling, voltage drop over distance. The stuff that turns a textbook answer into a passing one.
See each candidate gauge with a live pass/fail on voltage drop and the material cost across the full run length. Buy the size that passes โ not the size you guessed.
Organized like a real drawing set โ pick your discipline and go. No account, no cloud, no waiting on a signal.
A calculator you can't trust is worse than no calculator. Toolbelt shows its work and keeps working where you do.
20+ searchable NEC, IPC, and IRC articles in your pocket โ ampacity, fixture units, span tables. No subscription, no signal required.
Turn a calc into a quote. Your license number, your signature line, emailed straight from the truck before you pull off the job.
Every calc saved and filed under the job it belongs to. Filter by trade, star the ones you'll need again, find it next week.
The trade app world runs on subscriptions. This one doesn't. One price, everything unlocked, no one reaching back into your wallet next month.