Free Tools for Electricians

Electrical Calculators

Professional-grade NEC 2023 calculators. Free on the web, even better in the app.

Most Popular
Voltage Drop
NEC 2023 compliant voltage drop calculations for branch circuits and feeders. Supports copper/aluminum.
Essential
Wire Size Calculator
Find the correct wire gauge for any amperage based on NEC Table 310.16 with temperature and fill derating.
Conduit Fill
Calculate EMT, PVC, RMC, and IMC fill percentages for THHN, THWN, XHHW wire per NEC Chapter 9.
Box Fill
Calculate junction box, device box, and outlet box fill per NEC Article 314.16 requirements.
New
Dwelling Load
Calculate residential service load per NEC Article 220. Standard and optional methods with NEC 310.12 conductor sizing.

Get More in the App

All calculators work offline. Plus NEC code lookup, OJT hour tracking, exam prep, and more. Free to download.

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Why Use SparkShift Calculators?

Built by licensed electricians using NEC 2023 code requirements. Unlike generic calculators, our tools are designed specifically for the electrical trade.

Real NEC Table Data

Ampacities, conduit areas, and wire sizes from actual code tables

Derating Factors

Temperature correction and conduit fill adjustments built-in

Code References

Know exactly which NEC article your calculation is based on

Mobile-First Design

Works great on phones at the jobsite

Calculators Every Electrician Needs

Voltage Drop
3% & 5% limits
Wire Sizing
Auto derating
Conduit Fill
Pass inspection
Box Fill
NEC 314.16
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