Electrician Calculator +

Toffee Finance

In-app purchases

About this app

NEC-referenced calculators built for the jobsite: modern fields and pickers — no keystroke sequences to memorize, no manual required.

Wire Size & Voltage drop is free, forever. One one-time purchase unlocks everything else. No subscription, no ads, no account, 100% offline.

CALCULATORS

Voltage Drop — check a run or find the wire size for a max drop (free)
Wire Size & Ampacity — 60/75/90°C copper and aluminum, 240.4(D) breaker caps (free)
Ohm's Law — enter any two of V/I/R/P
Conduit Fill — THHN in EMT, mixed sizes, instant compliant/overfilled verdict
Box Fill — 314.16(B) volumes with per-item breakdown
Motor FLA estimate, Transformer sizing, Dwelling Load (220.82 optional method)
Quick Reference breaker/wire pairings and Conversions

BUILT FOR PROS

Inspector-ready PDF reports — export any result with inputs, NEC article citations, your company name and license number. Hand it to the inspector.
Saved jobs — group calculations by project, reopen them with every input restored, and export a whole job as one PDF packet for the submittal.
NEC edition switching — 2017, 2020, and 2023 citations included. All editions, one price, forever. No paid "code year" upgrades.
Glove-friendly controls, dark mode default for panel rooms and attics.

Results are estimates for planning and study. Verify against the current NEC and local amendments. Not a substitute for the NEC or a licensed electrician.

What’s new

Thanks for trying the app!

These changes fix some minor bugs