The inspector checks your math. Check it first.
Eight calculators verified against NEC 2023 and 2026. Every result shows its work and cites the code section. Print a PDF that holds up.
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Free web calculators, right on this site. No install, no account. Same verified engines, same code citations.
- calculators
- 8
- NEC editions
- 23/26
- PDF templates
- 6
- accounts or ads
- 0
Eight calculators. Two code cycles. Verified.
Wire size, voltage drop, conduit fill, box fill, dwelling load, motors, grounding and Ohm's law. Every table is independently verified against NEC 2023 and 2026.
- Wire SizeConductor size for a loadTable 310.16
- Voltage DropSize for a long runCh. 9 Table 8
- Conduit FillRaceway fill checkCh. 9 Tables 1, 4, 5
- Box FillBox volume check314.16
- Ohm's LawV, I, R and powerV = I·R
- Load CalcDwelling service size220.82PRO
- MotorFLC, OCPD, overloadArt 430PRO
- GroundingEGC and GEC sizingArt 250PRO
No black box. Every step, every citation.
Tap "Why this size?" on any result and see every step with its code section. No black box between your inputs and the answer. Tap the code chip and the table itself opens, with your row highlighted.
Leave the code book in the truck.
Tap the code chip on any result and the NEC table opens with your row highlighted. The number you submit and the table it came from, side by side.
A submittal, not a screenshot.
Combine calculations into a multi-page PDF submittal. Your company name, license and logo on the letterhead, a summary index, full code citations and a certification block with signature lines.
- Submittal
- Letterhead
- Service
- One-Sheet
- Field Report
- Worksheet
Six templates, from city submittal to client-ready service report. Checked against real county worksheet formats.
Works where the signal does not.
No signal, no problem. JobVolt is designed for the places electrical work actually happens.
- Works fully offline
Calculations, code tables, history and PDF export all work with zero bars in the crawlspace.
- Nothing gets lost
Every calculation saves to History automatically, so nothing slips between the panel and the truck.
- No account. No ads.
There is nothing to sign in to and no ad trackers. Your work stays on your device.
- Disponible en español
The app is available in Spanish. PDF reports and NEC terms stay in English, the language inspections expect.
Five calculators free. Upgrade when it earns its keep.
Free covers real work, not a teaser. Pro unlocks the rest of the toolbox. Purchases are billed through the App Store or Google Play.
For apprentices and occasional checks
- Five calculators with full derivations
- Every result cites its code section
- In-app NEC reference tables
- One report with 6 blocks
- Submittal PDF template
- Reports carry a small JobVolt line in the footer
- Calculation history
For working electricians and contractors
- 7-day free trial
- Load Calc, Motor and Grounding unlocked
- Unlimited reports and blocks
- All 6 PDF templates
- Your logo on the letterhead
Launch price for the first 90 days
- Everything in Pro Annual
- Pay once, keep it
- No subscription, no renewals
- Updates and NEC editions included
Monthly plan also available at $6.99/mo. Download free and upgrade in the app. Cancel anytime in your store account. Prices in USD.
Straight answers.
Questions electricians actually ask, answered without the sales pitch.
JobVolt is an NEC calculator app for US electricians. Every table is verified against NEC 2023 and 2026, every result shows its full derivation, and calculations export to inspector-ready PDF reports.
Yes. Wire size follows Table 310.16 with ambient temperature correction, conductor adjustment, terminal limits per 110.14(C), NM cable caps, parallel runs and the 83% dwelling rule. Every factor is shown in the derivation.
It uses Chapter 9 Table 8 conductor properties for single-phase and three-phase circuits. The result shows the full formula, your numbers in it, and the code reference.
Yes. Conduit fill follows Chapter 9 Tables 1, 4 and 5, with jam ratio warnings. Box fill per 314.16 is included too, with device, clamp and ground allowances.
Yes. Tables are verified against NEC 2023 and 2026, including the 2026 dwelling load changes such as the new 2 VA rule. NEC edition updates are free.
Yes, fully. Calculations, code tables, history and PDF export all work with no signal. There is no account to sign in to.
Your calculations and reports stay on your device. There is no account, no ads and no selling of data. The app may send anonymous crash reports and usage events to fix bugs. They are never linked to you.
No. JobVolt cites the code and shows the tables behind each result, but it is a reference tool, not the code itself. Your jurisdiction and inspector have final say.
Do the math. Print the proof. Pull the permit.
Free to start. Five calculators, full derivations and a submittal PDF, on the house.