About This Site
Electrical Toolbox is a collection of free online electrical calculation tools designed for electrical engineers, distribution designers, plant electricians, EV owners, and EE students.
Design Philosophy
- 100% Client-Side: All computation runs locally in your browser. Your input data never leaves your device — ideal for sensitive electrical parameters.
- Zero Friction: No registration, no login, no installation. Open your browser and start calculating.
- Standards-Compliant: Formulas and recommendations are based on GB/T (Chinese national standards), NEC (NFPA 70), and IEC, with each recommendation citing its source.
Tools Available
| Domain | Tools |
|---|---|
| EV Charging | Charging time estimator, charging power calculator |
| Power Distribution | Three-phase power / power factor correction, transformer capacity selection |
| Cables & Protection | Wire sizing (NEC AWG/kcmil), cable ampacity lookup (GB 50217), circuit breaker OCPD sizing |
| Energy & Cost | Residential electricity cost estimator, carbon emission estimation |
Disclaimer
The tools on this site are intended for educational reference and preliminary engineering estimation only. They do not replace the on-site judgment of a licensed electrician. All installation, construction, and energization decisions should be approved by your local Authority Having Jurisdiction (AHJ).
Tech Stack
- Hugo static site generator
- PaperMod theme
- Interactive calculators: vanilla HTML/CSS/JavaScript, zero backend dependencies
Contact & Feedback
For tool suggestions, standards updates, or bug reports, please open a GitHub Issue.
Privacy Commitment: This site uses no cookies, collects no user data, and integrates no third-party analytics. Your electrical parameters stay in your browser.