SparkCalc

Field calculators you can trust and electrician exam practice, in one app. Every result shows the code table it used and every step.

Coming soon to the App Store

No adsOne-time purchaseNo accountWorks offline

Voltage drop

Single-phase, three-phase and DC. Checks the allowed drop and finds the smallest wire that meets drop and ampacity.

Ampacity & wire size

Temperature and bundling corrections shown step by step, with the table and edition.

Conduit & box fill

Mixed conductors, a live cross-section and the smallest conduit. Saved conductor sets.

NEC · JIS · KEC

Switch standards in one tap. NEC 2023, Japan's Interior Wiring Code and Korea's KEC.

Exam prep (Japan)

Second-Class Electrician: explanations for every question, mock exams and wiring diagram practice for candidate problems, with more added through content updates. In Japanese.

iPhone & iPad

Made for iOS 26, Dark Mode, Dynamic Type and VoiceOver. 6 languages.

All calculators are free forever. SparkCalc Pro is a one-time purchase with Family Sharing that unlocks all exam content.